Miscellaneous Image Transformations

Enumerations
enum	cv::AdaptiveThresholdTypes {   cv::ADAPTIVE_THRESH_MEAN_C = 0,   cv::ADAPTIVE_THRESH_GAUSSIAN_C = 1 }
enum	cv::ColorConversionCodes {   cv::COLOR_BGR2BGRA = 0,   cv::COLOR_RGB2RGBA = COLOR_BGR2BGRA,   cv::COLOR_BGRA2BGR = 1,   cv::COLOR_RGBA2RGB = COLOR_BGRA2BGR,   cv::COLOR_BGR2RGBA = 2,   cv::COLOR_RGB2BGRA = COLOR_BGR2RGBA,   cv::COLOR_RGBA2BGR = 3,   cv::COLOR_BGRA2RGB = COLOR_RGBA2BGR,   cv::COLOR_BGR2RGB = 4,   cv::COLOR_RGB2BGR = COLOR_BGR2RGB,   cv::COLOR_BGRA2RGBA = 5,   cv::COLOR_RGBA2BGRA = COLOR_BGRA2RGBA,   cv::COLOR_BGR2GRAY = 6,   cv::COLOR_RGB2GRAY = 7,   cv::COLOR_GRAY2BGR = 8,   cv::COLOR_GRAY2RGB = COLOR_GRAY2BGR,   cv::COLOR_GRAY2BGRA = 9,   cv::COLOR_GRAY2RGBA = COLOR_GRAY2BGRA,   cv::COLOR_BGRA2GRAY = 10,   cv::COLOR_RGBA2GRAY = 11,   cv::COLOR_BGR2BGR565 = 12,   cv::COLOR_RGB2BGR565 = 13,   cv::COLOR_BGR5652BGR = 14,   cv::COLOR_BGR5652RGB = 15,   cv::COLOR_BGRA2BGR565 = 16,   cv::COLOR_RGBA2BGR565 = 17,   cv::COLOR_BGR5652BGRA = 18,   cv::COLOR_BGR5652RGBA = 19,   cv::COLOR_GRAY2BGR565 = 20,   cv::COLOR_BGR5652GRAY = 21,   cv::COLOR_BGR2BGR555 = 22,   cv::COLOR_RGB2BGR555 = 23,   cv::COLOR_BGR5552BGR = 24,   cv::COLOR_BGR5552RGB = 25,   cv::COLOR_BGRA2BGR555 = 26,   cv::COLOR_RGBA2BGR555 = 27,   cv::COLOR_BGR5552BGRA = 28,   cv::COLOR_BGR5552RGBA = 29,   cv::COLOR_GRAY2BGR555 = 30,   cv::COLOR_BGR5552GRAY = 31,   cv::COLOR_BGR2XYZ = 32,   cv::COLOR_RGB2XYZ = 33,   cv::COLOR_XYZ2BGR = 34,   cv::COLOR_XYZ2RGB = 35,   cv::COLOR_BGR2YCrCb = 36,   cv::COLOR_RGB2YCrCb = 37,   cv::COLOR_YCrCb2BGR = 38,   cv::COLOR_YCrCb2RGB = 39,   cv::COLOR_BGR2HSV = 40,   cv::COLOR_RGB2HSV = 41,   cv::COLOR_BGR2Lab = 44,   cv::COLOR_RGB2Lab = 45,   cv::COLOR_BGR2Luv = 50,   cv::COLOR_RGB2Luv = 51,   cv::COLOR_BGR2HLS = 52,   cv::COLOR_RGB2HLS = 53,   cv::COLOR_HSV2BGR = 54,   cv::COLOR_HSV2RGB = 55,   cv::COLOR_Lab2BGR = 56,   cv::COLOR_Lab2RGB = 57,   cv::COLOR_Luv2BGR = 58,   cv::COLOR_Luv2RGB = 59,   cv::COLOR_HLS2BGR = 60,   cv::COLOR_HLS2RGB = 61,   cv::COLOR_BGR2HSV_FULL = 66,   cv::COLOR_RGB2HSV_FULL = 67,   cv::COLOR_BGR2HLS_FULL = 68,   cv::COLOR_RGB2HLS_FULL = 69,   cv::COLOR_HSV2BGR_FULL = 70,   cv::COLOR_HSV2RGB_FULL = 71,   cv::COLOR_HLS2BGR_FULL = 72,   cv::COLOR_HLS2RGB_FULL = 73,   cv::COLOR_LBGR2Lab = 74,   cv::COLOR_LRGB2Lab = 75,   cv::COLOR_LBGR2Luv = 76,   cv::COLOR_LRGB2Luv = 77,   cv::COLOR_Lab2LBGR = 78,   cv::COLOR_Lab2LRGB = 79,   cv::COLOR_Luv2LBGR = 80,   cv::COLOR_Luv2LRGB = 81,   cv::COLOR_BGR2YUV = 82,   cv::COLOR_RGB2YUV = 83,   cv::COLOR_YUV2BGR = 84,   cv::COLOR_YUV2RGB = 85,   cv::COLOR_YUV2RGB_NV12 = 90,   cv::COLOR_YUV2BGR_NV12 = 91,   cv::COLOR_YUV2RGB_NV21 = 92,   cv::COLOR_YUV2BGR_NV21 = 93,   cv::COLOR_YUV420sp2RGB = COLOR_YUV2RGB_NV21,   cv::COLOR_YUV420sp2BGR = COLOR_YUV2BGR_NV21,   cv::COLOR_YUV2RGBA_NV12 = 94,   cv::COLOR_YUV2BGRA_NV12 = 95,   cv::COLOR_YUV2RGBA_NV21 = 96,   cv::COLOR_YUV2BGRA_NV21 = 97,   cv::COLOR_YUV420sp2RGBA = COLOR_YUV2RGBA_NV21,   cv::COLOR_YUV420sp2BGRA = COLOR_YUV2BGRA_NV21,   cv::COLOR_YUV2RGB_YV12 = 98,   cv::COLOR_YUV2BGR_YV12 = 99,   cv::COLOR_YUV2RGB_IYUV = 100,   cv::COLOR_YUV2BGR_IYUV = 101,   cv::COLOR_YUV2RGB_I420 = COLOR_YUV2RGB_IYUV,   cv::COLOR_YUV2BGR_I420 = COLOR_YUV2BGR_IYUV,   cv::COLOR_YUV420p2RGB = COLOR_YUV2RGB_YV12,   cv::COLOR_YUV420p2BGR = COLOR_YUV2BGR_YV12,   cv::COLOR_YUV2RGBA_YV12 = 102,   cv::COLOR_YUV2BGRA_YV12 = 103,   cv::COLOR_YUV2RGBA_IYUV = 104,   cv::COLOR_YUV2BGRA_IYUV = 105,   cv::COLOR_YUV2RGBA_I420 = COLOR_YUV2RGBA_IYUV,   cv::COLOR_YUV2BGRA_I420 = COLOR_YUV2BGRA_IYUV,   cv::COLOR_YUV420p2RGBA = COLOR_YUV2RGBA_YV12,   cv::COLOR_YUV420p2BGRA = COLOR_YUV2BGRA_YV12,   cv::COLOR_YUV2GRAY_420 = 106,   cv::COLOR_YUV2GRAY_NV21 = COLOR_YUV2GRAY_420,   cv::COLOR_YUV2GRAY_NV12 = COLOR_YUV2GRAY_420,   cv::COLOR_YUV2GRAY_YV12 = COLOR_YUV2GRAY_420,   cv::COLOR_YUV2GRAY_IYUV = COLOR_YUV2GRAY_420,   cv::COLOR_YUV2GRAY_I420 = COLOR_YUV2GRAY_420,   cv::COLOR_YUV420sp2GRAY = COLOR_YUV2GRAY_420,   cv::COLOR_YUV420p2GRAY = COLOR_YUV2GRAY_420,   cv::COLOR_YUV2RGB_UYVY = 107,   cv::COLOR_YUV2BGR_UYVY = 108,   cv::COLOR_YUV2RGB_Y422 = COLOR_YUV2RGB_UYVY,   cv::COLOR_YUV2BGR_Y422 = COLOR_YUV2BGR_UYVY,   cv::COLOR_YUV2RGB_UYNV = COLOR_YUV2RGB_UYVY,   cv::COLOR_YUV2BGR_UYNV = COLOR_YUV2BGR_UYVY,   cv::COLOR_YUV2RGBA_UYVY = 111,   cv::COLOR_YUV2BGRA_UYVY = 112,   cv::COLOR_YUV2RGBA_Y422 = COLOR_YUV2RGBA_UYVY,   cv::COLOR_YUV2BGRA_Y422 = COLOR_YUV2BGRA_UYVY,   cv::COLOR_YUV2RGBA_UYNV = COLOR_YUV2RGBA_UYVY,   cv::COLOR_YUV2BGRA_UYNV = COLOR_YUV2BGRA_UYVY,   cv::COLOR_YUV2RGB_YUY2 = 115,   cv::COLOR_YUV2BGR_YUY2 = 116,   cv::COLOR_YUV2RGB_YVYU = 117,   cv::COLOR_YUV2BGR_YVYU = 118,   cv::COLOR_YUV2RGB_YUYV = COLOR_YUV2RGB_YUY2,   cv::COLOR_YUV2BGR_YUYV = COLOR_YUV2BGR_YUY2,   cv::COLOR_YUV2RGB_YUNV = COLOR_YUV2RGB_YUY2,   cv::COLOR_YUV2BGR_YUNV = COLOR_YUV2BGR_YUY2,   cv::COLOR_YUV2RGBA_YUY2 = 119,   cv::COLOR_YUV2BGRA_YUY2 = 120,   cv::COLOR_YUV2RGBA_YVYU = 121,   cv::COLOR_YUV2BGRA_YVYU = 122,   cv::COLOR_YUV2RGBA_YUYV = COLOR_YUV2RGBA_YUY2,   cv::COLOR_YUV2BGRA_YUYV = COLOR_YUV2BGRA_YUY2,   cv::COLOR_YUV2RGBA_YUNV = COLOR_YUV2RGBA_YUY2,   cv::COLOR_YUV2BGRA_YUNV = COLOR_YUV2BGRA_YUY2,   cv::COLOR_YUV2GRAY_UYVY = 123,   cv::COLOR_YUV2GRAY_YUY2 = 124,   cv::COLOR_YUV2GRAY_Y422 = COLOR_YUV2GRAY_UYVY,   cv::COLOR_YUV2GRAY_UYNV = COLOR_YUV2GRAY_UYVY,   cv::COLOR_YUV2GRAY_YVYU = COLOR_YUV2GRAY_YUY2,   cv::COLOR_YUV2GRAY_YUYV = COLOR_YUV2GRAY_YUY2,   cv::COLOR_YUV2GRAY_YUNV = COLOR_YUV2GRAY_YUY2,   cv::COLOR_RGBA2mRGBA = 125,   cv::COLOR_mRGBA2RGBA = 126,   cv::COLOR_RGB2YUV_I420 = 127,   cv::COLOR_BGR2YUV_I420 = 128,   cv::COLOR_RGB2YUV_IYUV = COLOR_RGB2YUV_I420,   cv::COLOR_BGR2YUV_IYUV = COLOR_BGR2YUV_I420,   cv::COLOR_RGBA2YUV_I420 = 129,   cv::COLOR_BGRA2YUV_I420 = 130,   cv::COLOR_RGBA2YUV_IYUV = COLOR_RGBA2YUV_I420,   cv::COLOR_BGRA2YUV_IYUV = COLOR_BGRA2YUV_I420,   cv::COLOR_RGB2YUV_YV12 = 131,   cv::COLOR_BGR2YUV_YV12 = 132,   cv::COLOR_RGBA2YUV_YV12 = 133,   cv::COLOR_BGRA2YUV_YV12 = 134,   cv::COLOR_BayerBG2BGR = 46,   cv::COLOR_BayerGB2BGR = 47,   cv::COLOR_BayerRG2BGR = 48,   cv::COLOR_BayerGR2BGR = 49,   cv::COLOR_BayerBG2RGB = COLOR_BayerRG2BGR,   cv::COLOR_BayerGB2RGB = COLOR_BayerGR2BGR,   cv::COLOR_BayerRG2RGB = COLOR_BayerBG2BGR,   cv::COLOR_BayerGR2RGB = COLOR_BayerGB2BGR,   cv::COLOR_BayerBG2GRAY = 86,   cv::COLOR_BayerGB2GRAY = 87,   cv::COLOR_BayerRG2GRAY = 88,   cv::COLOR_BayerGR2GRAY = 89,   cv::COLOR_BayerBG2BGR_VNG = 62,   cv::COLOR_BayerGB2BGR_VNG = 63,   cv::COLOR_BayerRG2BGR_VNG = 64,   cv::COLOR_BayerGR2BGR_VNG = 65,   cv::COLOR_BayerBG2RGB_VNG = COLOR_BayerRG2BGR_VNG,   cv::COLOR_BayerGB2RGB_VNG = COLOR_BayerGR2BGR_VNG,   cv::COLOR_BayerRG2RGB_VNG = COLOR_BayerBG2BGR_VNG,   cv::COLOR_BayerGR2RGB_VNG = COLOR_BayerGB2BGR_VNG,   cv::COLOR_BayerBG2BGR_EA = 135,   cv::COLOR_BayerGB2BGR_EA = 136,   cv::COLOR_BayerRG2BGR_EA = 137,   cv::COLOR_BayerGR2BGR_EA = 138,   cv::COLOR_BayerBG2RGB_EA = COLOR_BayerRG2BGR_EA,   cv::COLOR_BayerGB2RGB_EA = COLOR_BayerGR2BGR_EA,   cv::COLOR_BayerRG2RGB_EA = COLOR_BayerBG2BGR_EA,   cv::COLOR_BayerGR2RGB_EA = COLOR_BayerGB2BGR_EA,   cv::COLOR_BayerBG2BGRA = 139,   cv::COLOR_BayerGB2BGRA = 140,   cv::COLOR_BayerRG2BGRA = 141,   cv::COLOR_BayerGR2BGRA = 142,   cv::COLOR_BayerBG2RGBA = COLOR_BayerRG2BGRA,   cv::COLOR_BayerGB2RGBA = COLOR_BayerGR2BGRA,   cv::COLOR_BayerRG2RGBA = COLOR_BayerBG2BGRA,   cv::COLOR_BayerGR2RGBA = COLOR_BayerGB2BGRA,   cv::COLOR_COLORCVT_MAX = 143 }
enum	cv::DistanceTransformLabelTypes {   cv::DIST_LABEL_CCOMP = 0,   cv::DIST_LABEL_PIXEL = 1 }
	distanceTransform algorithm flags More...
enum	cv::DistanceTransformMasks {   cv::DIST_MASK_3 = 3,   cv::DIST_MASK_5 = 5,   cv::DIST_MASK_PRECISE = 0 }
	Mask size for distance transform. More...
enum	cv::DistanceTypes {   cv::DIST_USER = -1,   cv::DIST_L1 = 1,   cv::DIST_L2 = 2,   cv::DIST_C = 3,   cv::DIST_L12 = 4,   cv::DIST_FAIR = 5,   cv::DIST_WELSCH = 6,   cv::DIST_HUBER = 7 }
enum	cv::FloodFillFlags {   cv::FLOODFILL_FIXED_RANGE = 1 << 16,   cv::FLOODFILL_MASK_ONLY = 1 << 17 }
	floodfill algorithm flags More...
enum	cv::GrabCutClasses {   cv::GC_BGD = 0,   cv::GC_FGD = 1,   cv::GC_PR_BGD = 2,   cv::GC_PR_FGD = 3 }
	class of the pixel in GrabCut algorithm More...
enum	cv::GrabCutModes {   cv::GC_INIT_WITH_RECT = 0,   cv::GC_INIT_WITH_MASK = 1,   cv::GC_EVAL = 2,   cv::GC_EVAL_FREEZE_MODEL = 3 }
	GrabCut algorithm flags. More...
enum	cv::ThresholdTypes {   cv::THRESH_BINARY = 0,   cv::THRESH_BINARY_INV = 1,   cv::THRESH_TRUNC = 2,   cv::THRESH_TOZERO = 3,   cv::THRESH_TOZERO_INV = 4,   cv::THRESH_MASK = 7,   cv::THRESH_OTSU = 8,   cv::THRESH_TRIANGLE = 16 }
enum	cv::UndistortTypes {   cv::PROJ_SPHERICAL_ORTHO = 0,   cv::PROJ_SPHERICAL_EQRECT = 1 }
	cv::undistort mode More...

Functions
void	cv::adaptiveThreshold (InputArray src, OutputArray dst, double maxValue, int adaptiveMethod, int thresholdType, int blockSize, double C)
	Applies an adaptive threshold to an array. More...
void	cv::cvtColor (InputArray src, OutputArray dst, int code, int dstCn=0)
	Converts an image from one color space to another. More...
void	cv::cvtColorTwoPlane (InputArray src1, InputArray src2, OutputArray dst, int code)
void	cv::distanceTransform (InputArray src, OutputArray dst, OutputArray labels, int distanceType, int maskSize, int labelType=DIST_LABEL_CCOMP)
	Calculates the distance to the closest zero pixel for each pixel of the source image. More...
void	cv::distanceTransform (InputArray src, OutputArray dst, int distanceType, int maskSize, int dstType=CV_32F)
int	cv::floodFill (InputOutputArray image, Point seedPoint, Scalar newVal, Rect *rect=0, Scalar loDiff=Scalar(), Scalar upDiff=Scalar(), int flags=4)
int	cv::floodFill (InputOutputArray image, InputOutputArray mask, Point seedPoint, Scalar newVal, Rect *rect=0, Scalar loDiff=Scalar(), Scalar upDiff=Scalar(), int flags=4)
	Fills a connected component with the given color. More...
void	cv::grabCut (InputArray img, InputOutputArray mask, Rect rect, InputOutputArray bgdModel, InputOutputArray fgdModel, int iterCount, int mode=GC_EVAL)
	Runs the GrabCut algorithm. More...
void	cv::integral (InputArray src, OutputArray sum, int sdepth=-1)
void	cv::integral (InputArray src, OutputArray sum, OutputArray sqsum, int sdepth=-1, int sqdepth=-1)
void	cv::integral (InputArray src, OutputArray sum, OutputArray sqsum, OutputArray tilted, int sdepth=-1, int sqdepth=-1)
	Calculates the integral of an image. More...
double	cv::threshold (InputArray src, OutputArray dst, double thresh, double maxval, int type)
	Applies a fixed-level threshold to each array element. More...
void	cv::watershed (InputArray image, InputOutputArray markers)
	Performs a marker-based image segmentation using the watershed algorithm. More...

Detailed Description

Enumeration Type Documentation

AdaptiveThresholdTypes

enum cv::AdaptiveThresholdTypes

adaptive threshold algorithm

See also

adaptiveThreshold

Enumerator
ADAPTIVE_THRESH_MEAN_C  Python: cv.ADAPTIVE_THRESH_MEAN_C	the threshold value \(T(x,y)\) is a mean of the \(\texttt{blockSize} \times \texttt{blockSize}\) neighborhood of \((x, y)\) minus C
ADAPTIVE_THRESH_GAUSSIAN_C  Python: cv.ADAPTIVE_THRESH_GAUSSIAN_C	the threshold value \(T(x, y)\) is a weighted sum (cross-correlation with a Gaussian window) of the \(\texttt{blockSize} \times \texttt{blockSize}\) neighborhood of \((x, y)\) minus C . The default sigma (standard deviation) is used for the specified blockSize . See getGaussianKernel

ColorConversionCodes

enum cv::ColorConversionCodes

the color conversion code

See also

Color conversions

Enumerator
COLOR_BGR2BGRA  Python: cv.COLOR_BGR2BGRA	add alpha channel to RGB or BGR image
COLOR_RGB2RGBA  Python: cv.COLOR_RGB2RGBA
COLOR_BGRA2BGR  Python: cv.COLOR_BGRA2BGR	remove alpha channel from RGB or BGR image
COLOR_RGBA2RGB  Python: cv.COLOR_RGBA2RGB
COLOR_BGR2RGBA  Python: cv.COLOR_BGR2RGBA	convert between RGB and BGR color spaces (with or without alpha channel)
COLOR_RGB2BGRA  Python: cv.COLOR_RGB2BGRA
COLOR_RGBA2BGR  Python: cv.COLOR_RGBA2BGR
COLOR_BGRA2RGB  Python: cv.COLOR_BGRA2RGB
COLOR_BGR2RGB  Python: cv.COLOR_BGR2RGB
COLOR_RGB2BGR  Python: cv.COLOR_RGB2BGR
COLOR_BGRA2RGBA  Python: cv.COLOR_BGRA2RGBA
COLOR_RGBA2BGRA  Python: cv.COLOR_RGBA2BGRA
COLOR_BGR2GRAY  Python: cv.COLOR_BGR2GRAY	convert between RGB/BGR and grayscale, color conversions
COLOR_RGB2GRAY  Python: cv.COLOR_RGB2GRAY
COLOR_GRAY2BGR  Python: cv.COLOR_GRAY2BGR
COLOR_GRAY2RGB  Python: cv.COLOR_GRAY2RGB
COLOR_GRAY2BGRA  Python: cv.COLOR_GRAY2BGRA
COLOR_GRAY2RGBA  Python: cv.COLOR_GRAY2RGBA
COLOR_BGRA2GRAY  Python: cv.COLOR_BGRA2GRAY
COLOR_RGBA2GRAY  Python: cv.COLOR_RGBA2GRAY
COLOR_BGR2BGR565  Python: cv.COLOR_BGR2BGR565	convert between RGB/BGR and BGR565 (16-bit images)
COLOR_RGB2BGR565  Python: cv.COLOR_RGB2BGR565
COLOR_BGR5652BGR  Python: cv.COLOR_BGR5652BGR
COLOR_BGR5652RGB  Python: cv.COLOR_BGR5652RGB
COLOR_BGRA2BGR565  Python: cv.COLOR_BGRA2BGR565
COLOR_RGBA2BGR565  Python: cv.COLOR_RGBA2BGR565
COLOR_BGR5652BGRA  Python: cv.COLOR_BGR5652BGRA
COLOR_BGR5652RGBA  Python: cv.COLOR_BGR5652RGBA
COLOR_GRAY2BGR565  Python: cv.COLOR_GRAY2BGR565	convert between grayscale to BGR565 (16-bit images)
COLOR_BGR5652GRAY  Python: cv.COLOR_BGR5652GRAY
COLOR_BGR2BGR555  Python: cv.COLOR_BGR2BGR555	convert between RGB/BGR and BGR555 (16-bit images)
COLOR_RGB2BGR555  Python: cv.COLOR_RGB2BGR555
COLOR_BGR5552BGR  Python: cv.COLOR_BGR5552BGR
COLOR_BGR5552RGB  Python: cv.COLOR_BGR5552RGB
COLOR_BGRA2BGR555  Python: cv.COLOR_BGRA2BGR555
COLOR_RGBA2BGR555  Python: cv.COLOR_RGBA2BGR555
COLOR_BGR5552BGRA  Python: cv.COLOR_BGR5552BGRA
COLOR_BGR5552RGBA  Python: cv.COLOR_BGR5552RGBA
COLOR_GRAY2BGR555  Python: cv.COLOR_GRAY2BGR555	convert between grayscale and BGR555 (16-bit images)
COLOR_BGR5552GRAY  Python: cv.COLOR_BGR5552GRAY
COLOR_BGR2XYZ  Python: cv.COLOR_BGR2XYZ	convert RGB/BGR to CIE XYZ, color conversions
COLOR_RGB2XYZ  Python: cv.COLOR_RGB2XYZ
COLOR_XYZ2BGR  Python: cv.COLOR_XYZ2BGR
COLOR_XYZ2RGB  Python: cv.COLOR_XYZ2RGB
COLOR_BGR2YCrCb  Python: cv.COLOR_BGR2YCrCb	convert RGB/BGR to luma-chroma (aka YCC), color conversions
COLOR_RGB2YCrCb  Python: cv.COLOR_RGB2YCrCb
COLOR_YCrCb2BGR  Python: cv.COLOR_YCrCb2BGR
COLOR_YCrCb2RGB  Python: cv.COLOR_YCrCb2RGB
COLOR_BGR2HSV  Python: cv.COLOR_BGR2HSV	convert RGB/BGR to HSV (hue saturation value), color conversions
COLOR_RGB2HSV  Python: cv.COLOR_RGB2HSV
COLOR_BGR2Lab  Python: cv.COLOR_BGR2Lab	convert RGB/BGR to CIE Lab, color conversions
COLOR_RGB2Lab  Python: cv.COLOR_RGB2Lab
COLOR_BGR2Luv  Python: cv.COLOR_BGR2Luv	convert RGB/BGR to CIE Luv, color conversions
COLOR_RGB2Luv  Python: cv.COLOR_RGB2Luv
COLOR_BGR2HLS  Python: cv.COLOR_BGR2HLS	convert RGB/BGR to HLS (hue lightness saturation), color conversions
COLOR_RGB2HLS  Python: cv.COLOR_RGB2HLS
COLOR_HSV2BGR  Python: cv.COLOR_HSV2BGR	backward conversions to RGB/BGR
COLOR_HSV2RGB  Python: cv.COLOR_HSV2RGB
COLOR_Lab2BGR  Python: cv.COLOR_Lab2BGR
COLOR_Lab2RGB  Python: cv.COLOR_Lab2RGB
COLOR_Luv2BGR  Python: cv.COLOR_Luv2BGR
COLOR_Luv2RGB  Python: cv.COLOR_Luv2RGB
COLOR_HLS2BGR  Python: cv.COLOR_HLS2BGR
COLOR_HLS2RGB  Python: cv.COLOR_HLS2RGB
COLOR_BGR2HSV_FULL  Python: cv.COLOR_BGR2HSV_FULL
COLOR_RGB2HSV_FULL  Python: cv.COLOR_RGB2HSV_FULL
COLOR_BGR2HLS_FULL  Python: cv.COLOR_BGR2HLS_FULL
COLOR_RGB2HLS_FULL  Python: cv.COLOR_RGB2HLS_FULL
COLOR_HSV2BGR_FULL  Python: cv.COLOR_HSV2BGR_FULL
COLOR_HSV2RGB_FULL  Python: cv.COLOR_HSV2RGB_FULL
COLOR_HLS2BGR_FULL  Python: cv.COLOR_HLS2BGR_FULL
COLOR_HLS2RGB_FULL  Python: cv.COLOR_HLS2RGB_FULL
COLOR_LBGR2Lab  Python: cv.COLOR_LBGR2Lab
COLOR_LRGB2Lab  Python: cv.COLOR_LRGB2Lab
COLOR_LBGR2Luv  Python: cv.COLOR_LBGR2Luv
COLOR_LRGB2Luv  Python: cv.COLOR_LRGB2Luv
COLOR_Lab2LBGR  Python: cv.COLOR_Lab2LBGR
COLOR_Lab2LRGB  Python: cv.COLOR_Lab2LRGB
COLOR_Luv2LBGR  Python: cv.COLOR_Luv2LBGR
COLOR_Luv2LRGB  Python: cv.COLOR_Luv2LRGB
COLOR_BGR2YUV  Python: cv.COLOR_BGR2YUV	convert between RGB/BGR and YUV
COLOR_RGB2YUV  Python: cv.COLOR_RGB2YUV
COLOR_YUV2BGR  Python: cv.COLOR_YUV2BGR
COLOR_YUV2RGB  Python: cv.COLOR_YUV2RGB
COLOR_YUV2RGB_NV12  Python: cv.COLOR_YUV2RGB_NV12	YUV 4:2:0 family to RGB.
COLOR_YUV2BGR_NV12  Python: cv.COLOR_YUV2BGR_NV12
COLOR_YUV2RGB_NV21  Python: cv.COLOR_YUV2RGB_NV21
COLOR_YUV2BGR_NV21  Python: cv.COLOR_YUV2BGR_NV21
COLOR_YUV420sp2RGB  Python: cv.COLOR_YUV420sp2RGB
COLOR_YUV420sp2BGR  Python: cv.COLOR_YUV420sp2BGR
COLOR_YUV2RGBA_NV12  Python: cv.COLOR_YUV2RGBA_NV12
COLOR_YUV2BGRA_NV12  Python: cv.COLOR_YUV2BGRA_NV12
COLOR_YUV2RGBA_NV21  Python: cv.COLOR_YUV2RGBA_NV21
COLOR_YUV2BGRA_NV21  Python: cv.COLOR_YUV2BGRA_NV21
COLOR_YUV420sp2RGBA  Python: cv.COLOR_YUV420sp2RGBA
COLOR_YUV420sp2BGRA  Python: cv.COLOR_YUV420sp2BGRA
COLOR_YUV2RGB_YV12  Python: cv.COLOR_YUV2RGB_YV12
COLOR_YUV2BGR_YV12  Python: cv.COLOR_YUV2BGR_YV12
COLOR_YUV2RGB_IYUV  Python: cv.COLOR_YUV2RGB_IYUV
COLOR_YUV2BGR_IYUV  Python: cv.COLOR_YUV2BGR_IYUV
COLOR_YUV2RGB_I420  Python: cv.COLOR_YUV2RGB_I420
COLOR_YUV2BGR_I420  Python: cv.COLOR_YUV2BGR_I420
COLOR_YUV420p2RGB  Python: cv.COLOR_YUV420p2RGB
COLOR_YUV420p2BGR  Python: cv.COLOR_YUV420p2BGR
COLOR_YUV2RGBA_YV12  Python: cv.COLOR_YUV2RGBA_YV12
COLOR_YUV2BGRA_YV12  Python: cv.COLOR_YUV2BGRA_YV12
COLOR_YUV2RGBA_IYUV  Python: cv.COLOR_YUV2RGBA_IYUV
COLOR_YUV2BGRA_IYUV  Python: cv.COLOR_YUV2BGRA_IYUV
COLOR_YUV2RGBA_I420  Python: cv.COLOR_YUV2RGBA_I420
COLOR_YUV2BGRA_I420  Python: cv.COLOR_YUV2BGRA_I420
COLOR_YUV420p2RGBA  Python: cv.COLOR_YUV420p2RGBA
COLOR_YUV420p2BGRA  Python: cv.COLOR_YUV420p2BGRA
COLOR_YUV2GRAY_420  Python: cv.COLOR_YUV2GRAY_420
COLOR_YUV2GRAY_NV21  Python: cv.COLOR_YUV2GRAY_NV21
COLOR_YUV2GRAY_NV12  Python: cv.COLOR_YUV2GRAY_NV12
COLOR_YUV2GRAY_YV12  Python: cv.COLOR_YUV2GRAY_YV12
COLOR_YUV2GRAY_IYUV  Python: cv.COLOR_YUV2GRAY_IYUV
COLOR_YUV2GRAY_I420  Python: cv.COLOR_YUV2GRAY_I420
COLOR_YUV420sp2GRAY  Python: cv.COLOR_YUV420sp2GRAY
COLOR_YUV420p2GRAY  Python: cv.COLOR_YUV420p2GRAY
COLOR_YUV2RGB_UYVY  Python: cv.COLOR_YUV2RGB_UYVY	YUV 4:2:2 family to RGB.
COLOR_YUV2BGR_UYVY  Python: cv.COLOR_YUV2BGR_UYVY
COLOR_YUV2RGB_Y422  Python: cv.COLOR_YUV2RGB_Y422
COLOR_YUV2BGR_Y422  Python: cv.COLOR_YUV2BGR_Y422
COLOR_YUV2RGB_UYNV  Python: cv.COLOR_YUV2RGB_UYNV
COLOR_YUV2BGR_UYNV  Python: cv.COLOR_YUV2BGR_UYNV
COLOR_YUV2RGBA_UYVY  Python: cv.COLOR_YUV2RGBA_UYVY
COLOR_YUV2BGRA_UYVY  Python: cv.COLOR_YUV2BGRA_UYVY
COLOR_YUV2RGBA_Y422  Python: cv.COLOR_YUV2RGBA_Y422
COLOR_YUV2BGRA_Y422  Python: cv.COLOR_YUV2BGRA_Y422
COLOR_YUV2RGBA_UYNV  Python: cv.COLOR_YUV2RGBA_UYNV
COLOR_YUV2BGRA_UYNV  Python: cv.COLOR_YUV2BGRA_UYNV
COLOR_YUV2RGB_YUY2  Python: cv.COLOR_YUV2RGB_YUY2
COLOR_YUV2BGR_YUY2  Python: cv.COLOR_YUV2BGR_YUY2
COLOR_YUV2RGB_YVYU  Python: cv.COLOR_YUV2RGB_YVYU
COLOR_YUV2BGR_YVYU  Python: cv.COLOR_YUV2BGR_YVYU
COLOR_YUV2RGB_YUYV  Python: cv.COLOR_YUV2RGB_YUYV
COLOR_YUV2BGR_YUYV  Python: cv.COLOR_YUV2BGR_YUYV
COLOR_YUV2RGB_YUNV  Python: cv.COLOR_YUV2RGB_YUNV
COLOR_YUV2BGR_YUNV  Python: cv.COLOR_YUV2BGR_YUNV
COLOR_YUV2RGBA_YUY2  Python: cv.COLOR_YUV2RGBA_YUY2
COLOR_YUV2BGRA_YUY2  Python: cv.COLOR_YUV2BGRA_YUY2
COLOR_YUV2RGBA_YVYU  Python: cv.COLOR_YUV2RGBA_YVYU
COLOR_YUV2BGRA_YVYU  Python: cv.COLOR_YUV2BGRA_YVYU
COLOR_YUV2RGBA_YUYV  Python: cv.COLOR_YUV2RGBA_YUYV
COLOR_YUV2BGRA_YUYV  Python: cv.COLOR_YUV2BGRA_YUYV
COLOR_YUV2RGBA_YUNV  Python: cv.COLOR_YUV2RGBA_YUNV
COLOR_YUV2BGRA_YUNV  Python: cv.COLOR_YUV2BGRA_YUNV
COLOR_YUV2GRAY_UYVY  Python: cv.COLOR_YUV2GRAY_UYVY
COLOR_YUV2GRAY_YUY2  Python: cv.COLOR_YUV2GRAY_YUY2
COLOR_YUV2GRAY_Y422  Python: cv.COLOR_YUV2GRAY_Y422
COLOR_YUV2GRAY_UYNV  Python: cv.COLOR_YUV2GRAY_UYNV
COLOR_YUV2GRAY_YVYU  Python: cv.COLOR_YUV2GRAY_YVYU
COLOR_YUV2GRAY_YUYV  Python: cv.COLOR_YUV2GRAY_YUYV
COLOR_YUV2GRAY_YUNV  Python: cv.COLOR_YUV2GRAY_YUNV
COLOR_RGBA2mRGBA  Python: cv.COLOR_RGBA2mRGBA	alpha premultiplication
COLOR_mRGBA2RGBA  Python: cv.COLOR_mRGBA2RGBA
COLOR_RGB2YUV_I420  Python: cv.COLOR_RGB2YUV_I420	RGB to YUV 4:2:0 family.
COLOR_BGR2YUV_I420  Python: cv.COLOR_BGR2YUV_I420
COLOR_RGB2YUV_IYUV  Python: cv.COLOR_RGB2YUV_IYUV
COLOR_BGR2YUV_IYUV  Python: cv.COLOR_BGR2YUV_IYUV
COLOR_RGBA2YUV_I420  Python: cv.COLOR_RGBA2YUV_I420
COLOR_BGRA2YUV_I420  Python: cv.COLOR_BGRA2YUV_I420
COLOR_RGBA2YUV_IYUV  Python: cv.COLOR_RGBA2YUV_IYUV
COLOR_BGRA2YUV_IYUV  Python: cv.COLOR_BGRA2YUV_IYUV
COLOR_RGB2YUV_YV12  Python: cv.COLOR_RGB2YUV_YV12
COLOR_BGR2YUV_YV12  Python: cv.COLOR_BGR2YUV_YV12
COLOR_RGBA2YUV_YV12  Python: cv.COLOR_RGBA2YUV_YV12
COLOR_BGRA2YUV_YV12  Python: cv.COLOR_BGRA2YUV_YV12
COLOR_BayerBG2BGR  Python: cv.COLOR_BayerBG2BGR	Demosaicing.
COLOR_BayerGB2BGR  Python: cv.COLOR_BayerGB2BGR
COLOR_BayerRG2BGR  Python: cv.COLOR_BayerRG2BGR
COLOR_BayerGR2BGR  Python: cv.COLOR_BayerGR2BGR
COLOR_BayerBG2RGB  Python: cv.COLOR_BayerBG2RGB
COLOR_BayerGB2RGB  Python: cv.COLOR_BayerGB2RGB
COLOR_BayerRG2RGB  Python: cv.COLOR_BayerRG2RGB
COLOR_BayerGR2RGB  Python: cv.COLOR_BayerGR2RGB
COLOR_BayerBG2GRAY  Python: cv.COLOR_BayerBG2GRAY
COLOR_BayerGB2GRAY  Python: cv.COLOR_BayerGB2GRAY
COLOR_BayerRG2GRAY  Python: cv.COLOR_BayerRG2GRAY
COLOR_BayerGR2GRAY  Python: cv.COLOR_BayerGR2GRAY
COLOR_BayerBG2BGR_VNG  Python: cv.COLOR_BayerBG2BGR_VNG	Demosaicing using Variable Number of Gradients.
COLOR_BayerGB2BGR_VNG  Python: cv.COLOR_BayerGB2BGR_VNG
COLOR_BayerRG2BGR_VNG  Python: cv.COLOR_BayerRG2BGR_VNG
COLOR_BayerGR2BGR_VNG  Python: cv.COLOR_BayerGR2BGR_VNG
COLOR_BayerBG2RGB_VNG  Python: cv.COLOR_BayerBG2RGB_VNG
COLOR_BayerGB2RGB_VNG  Python: cv.COLOR_BayerGB2RGB_VNG
COLOR_BayerRG2RGB_VNG  Python: cv.COLOR_BayerRG2RGB_VNG
COLOR_BayerGR2RGB_VNG  Python: cv.COLOR_BayerGR2RGB_VNG
COLOR_BayerBG2BGR_EA  Python: cv.COLOR_BayerBG2BGR_EA	Edge-Aware Demosaicing.
COLOR_BayerGB2BGR_EA  Python: cv.COLOR_BayerGB2BGR_EA
COLOR_BayerRG2BGR_EA  Python: cv.COLOR_BayerRG2BGR_EA
COLOR_BayerGR2BGR_EA  Python: cv.COLOR_BayerGR2BGR_EA
COLOR_BayerBG2RGB_EA  Python: cv.COLOR_BayerBG2RGB_EA
COLOR_BayerGB2RGB_EA  Python: cv.COLOR_BayerGB2RGB_EA
COLOR_BayerRG2RGB_EA  Python: cv.COLOR_BayerRG2RGB_EA
COLOR_BayerGR2RGB_EA  Python: cv.COLOR_BayerGR2RGB_EA
COLOR_BayerBG2BGRA  Python: cv.COLOR_BayerBG2BGRA	Demosaicing with alpha channel.
COLOR_BayerGB2BGRA  Python: cv.COLOR_BayerGB2BGRA
COLOR_BayerRG2BGRA  Python: cv.COLOR_BayerRG2BGRA
COLOR_BayerGR2BGRA  Python: cv.COLOR_BayerGR2BGRA
COLOR_BayerBG2RGBA  Python: cv.COLOR_BayerBG2RGBA
COLOR_BayerGB2RGBA  Python: cv.COLOR_BayerGB2RGBA
COLOR_BayerRG2RGBA  Python: cv.COLOR_BayerRG2RGBA
COLOR_BayerGR2RGBA  Python: cv.COLOR_BayerGR2RGBA
COLOR_COLORCVT_MAX  Python: cv.COLOR_COLORCVT_MAX

DistanceTransformLabelTypes

enum cv::DistanceTransformLabelTypes

distanceTransform algorithm flags

Enumerator
DIST_LABEL_CCOMP  Python: cv.DIST_LABEL_CCOMP	each connected component of zeros in src (as well as all the non-zero pixels closest to the connected component) will be assigned the same label
DIST_LABEL_PIXEL  Python: cv.DIST_LABEL_PIXEL	each zero pixel (and all the non-zero pixels closest to it) gets its own label.

DistanceTransformMasks

enum cv::DistanceTransformMasks

Mask size for distance transform.

Enumerator
DIST_MASK_3  Python: cv.DIST_MASK_3	mask=3
DIST_MASK_5  Python: cv.DIST_MASK_5	mask=5
DIST_MASK_PRECISE  Python: cv.DIST_MASK_PRECISE

DistanceTypes

enum cv::DistanceTypes

Distance types for Distance Transform and M-estimators

See also

distanceTransform, fitLine

Enumerator
DIST_USER  Python: cv.DIST_USER	User defined distance.
DIST_L1  Python: cv.DIST_L1	distance = |x1-x2| + |y1-y2|
DIST_L2  Python: cv.DIST_L2	the simple euclidean distance
DIST_C  Python: cv.DIST_C	distance = max(|x1-x2|,|y1-y2|)
DIST_L12  Python: cv.DIST_L12	L1-L2 metric: distance = 2(sqrt(1+x*x/2) - 1))
DIST_FAIR  Python: cv.DIST_FAIR	distance = c^2(|x|/c-log(1+|x|/c)), c = 1.3998
DIST_WELSCH  Python: cv.DIST_WELSCH	distance = c^2/2(1-exp(-(x/c)^2)), c = 2.9846
DIST_HUBER  Python: cv.DIST_HUBER	distance = |x|<c ? x^2/2 : c(|x|-c/2), c=1.345

FloodFillFlags

enum cv::FloodFillFlags

floodfill algorithm flags

Enumerator
FLOODFILL_FIXED_RANGE  Python: cv.FLOODFILL_FIXED_RANGE	If set, the difference between the current pixel and seed pixel is considered. Otherwise, the difference between neighbor pixels is considered (that is, the range is floating).
FLOODFILL_MASK_ONLY  Python: cv.FLOODFILL_MASK_ONLY	If set, the function does not change the image ( newVal is ignored), and only fills the mask with the value specified in bits 8-16 of flags as described above. This option only make sense in function variants that have the mask parameter.

GrabCutClasses

enum cv::GrabCutClasses

class of the pixel in GrabCut algorithm

Enumerator
GC_BGD  Python: cv.GC_BGD	an obvious background pixels
GC_FGD  Python: cv.GC_FGD	an obvious foreground (object) pixel
GC_PR_BGD  Python: cv.GC_PR_BGD	a possible background pixel
GC_PR_FGD  Python: cv.GC_PR_FGD	a possible foreground pixel

GrabCutModes

enum cv::GrabCutModes

GrabCut algorithm flags.

Enumerator
GC_INIT_WITH_RECT  Python: cv.GC_INIT_WITH_RECT	The function initializes the state and the mask using the provided rectangle. After that it runs iterCount iterations of the algorithm.
GC_INIT_WITH_MASK  Python: cv.GC_INIT_WITH_MASK	The function initializes the state using the provided mask. Note that GC_INIT_WITH_RECT and GC_INIT_WITH_MASK can be combined. Then, all the pixels outside of the ROI are automatically initialized with GC_BGD .
GC_EVAL  Python: cv.GC_EVAL	The value means that the algorithm should just resume.
GC_EVAL_FREEZE_MODEL  Python: cv.GC_EVAL_FREEZE_MODEL	The value means that the algorithm should just run the grabCut algorithm (a single iteration) with the fixed model

ThresholdTypes

enum cv::ThresholdTypes

type of the threshold operation

threshold types

Enumerator
THRESH_BINARY  Python: cv.THRESH_BINARY	\[\texttt{dst} (x,y) = \fork{\texttt{maxval}}{if \(\texttt{src}(x,y) > \texttt{thresh}\)}{0}{otherwise}\]
THRESH_BINARY_INV  Python: cv.THRESH_BINARY_INV	\[\texttt{dst} (x,y) = \fork{0}{if \(\texttt{src}(x,y) > \texttt{thresh}\)}{\texttt{maxval}}{otherwise}\]
THRESH_TRUNC  Python: cv.THRESH_TRUNC	\[\texttt{dst} (x,y) = \fork{\texttt{threshold}}{if \(\texttt{src}(x,y) > \texttt{thresh}\)}{\texttt{src}(x,y)}{otherwise}\]
THRESH_TOZERO  Python: cv.THRESH_TOZERO	\[\texttt{dst} (x,y) = \fork{\texttt{src}(x,y)}{if \(\texttt{src}(x,y) > \texttt{thresh}\)}{0}{otherwise}\]
THRESH_TOZERO_INV  Python: cv.THRESH_TOZERO_INV	\[\texttt{dst} (x,y) = \fork{0}{if \(\texttt{src}(x,y) > \texttt{thresh}\)}{\texttt{src}(x,y)}{otherwise}\]
THRESH_MASK  Python: cv.THRESH_MASK
THRESH_OTSU  Python: cv.THRESH_OTSU	flag, use Otsu algorithm to choose the optimal threshold value
THRESH_TRIANGLE  Python: cv.THRESH_TRIANGLE	flag, use Triangle algorithm to choose the optimal threshold value

UndistortTypes

enum cv::UndistortTypes

cv::undistort mode

Enumerator
PROJ_SPHERICAL_ORTHO  Python: cv.PROJ_SPHERICAL_ORTHO
PROJ_SPHERICAL_EQRECT  Python: cv.PROJ_SPHERICAL_EQRECT

Function Documentation

adaptiveThreshold()

void cv::adaptiveThreshold	(	InputArray	src,
		OutputArray	dst,
		double	maxValue,
		int	adaptiveMethod,
		int	thresholdType,
		int	blockSize,
		double	C
	)

Python:
	dst	=	cv.adaptiveThreshold(	src, maxValue, adaptiveMethod, thresholdType, blockSize, C[, dst]	)

Applies an adaptive threshold to an array.

The function transforms a grayscale image to a binary image according to the formulae:

• THRESH_BINARY

  \[dst(x,y) = \fork{\texttt{maxValue}}{if \(src(x,y) > T(x,y)\)}{0}{otherwise}\]

• THRESH_BINARY_INV

  \[dst(x,y) = \fork{0}{if \(src(x,y) > T(x,y)\)}{\texttt{maxValue}}{otherwise}\]

  where \(T(x,y)\) is a threshold calculated individually for each pixel (see adaptiveMethod parameter).

The function can process the image in-place.

Parameters

src	Source 8-bit single-channel image.
dst	Destination image of the same size and the same type as src.
maxValue	Non-zero value assigned to the pixels for which the condition is satisfied
adaptiveMethod	Adaptive thresholding algorithm to use, see AdaptiveThresholdTypes. The BORDER_REPLICATE | BORDER_ISOLATED is used to process boundaries.
thresholdType	Thresholding type that must be either THRESH_BINARY or THRESH_BINARY_INV, see ThresholdTypes.
blockSize	Size of a pixel neighborhood that is used to calculate a threshold value for the pixel: 3, 5, 7, and so on.
C	Constant subtracted from the mean or weighted mean (see the details below). Normally, it is positive but may be zero or negative as well.

See also

threshold, blur, GaussianBlur

cvtColor()

void cv::cvtColor	(	InputArray	src,
		OutputArray	dst,
		int	code,
		int	dstCn = 0
	)

Python:
	dst	=	cv.cvtColor(	src, code[, dst[, dstCn]]	)

Converts an image from one color space to another.

The function converts an input image from one color space to another. In case of a transformation to-from RGB color space, the order of the channels should be specified explicitly (RGB or BGR). Note that the default color format in OpenCV is often referred to as RGB but it is actually BGR (the bytes are reversed). So the first byte in a standard (24-bit) color image will be an 8-bit Blue component, the second byte will be Green, and the third byte will be Red. The fourth, fifth, and sixth bytes would then be the second pixel (Blue, then Green, then Red), and so on.

The conventional ranges for R, G, and B channel values are:

• 0 to 255 for CV_8U images
• 0 to 65535 for CV_16U images
• 0 to 1 for CV_32F images

In case of linear transformations, the range does not matter. But in case of a non-linear transformation, an input RGB image should be normalized to the proper value range to get the correct results, for example, for RGB \(\rightarrow\) L*u*v* transformation. For example, if you have a 32-bit floating-point image directly converted from an 8-bit image without any scaling, then it will have the 0..255 value range instead of 0..1 assumed by the function. So, before calling cvtColor , you need first to scale the image down:

img *= 1./255;
cvtColor(img, img, COLOR_BGR2Luv);

If you use cvtColor with 8-bit images, the conversion will have some information lost. For many applications, this will not be noticeable but it is recommended to use 32-bit images in applications that need the full range of colors or that convert an image before an operation and then convert back.

If conversion adds the alpha channel, its value will set to the maximum of corresponding channel range: 255 for CV_8U, 65535 for CV_16U, 1 for CV_32F.

Parameters

src	input image: 8-bit unsigned, 16-bit unsigned ( CV_16UC... ), or single-precision floating-point.
dst	output image of the same size and depth as src.
code	color space conversion code (see ColorConversionCodes).
dstCn	number of channels in the destination image; if the parameter is 0, the number of the channels is derived automatically from src and code.

See also

Color conversions

Examples:

samples/cpp/camshiftdemo.cpp, samples/cpp/edge.cpp, samples/cpp/facedetect.cpp, samples/cpp/ffilldemo.cpp, samples/cpp/lkdemo.cpp, samples/cpp/train_HOG.cpp, samples/cpp/tutorial_code/ImgTrans/houghcircles.cpp, samples/cpp/tutorial_code/ImgTrans/houghlines.cpp, samples/cpp/tutorial_code/ImgTrans/Sobel_Demo.cpp, samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp, samples/cpp/watershed.cpp, samples/dnn/colorization.cpp, and samples/tapi/hog.cpp.

cvtColorTwoPlane()

void cv::cvtColorTwoPlane	(	InputArray	src1,
		InputArray	src2,
		OutputArray	dst,
		int	code
	)

Python:
	dst	=	cv.cvtColorTwoPlane(	src1, src2, code[, dst]	)

distanceTransform() [1/2]

void cv::distanceTransform	(	InputArray	src,
		OutputArray	dst,
		OutputArray	labels,
		int	distanceType,
		int	maskSize,
		int	labelType = DIST_LABEL_CCOMP
	)

Python:
	dst	=	cv.distanceTransform(	src, distanceType, maskSize[, dst[, dstType]]	)
	dst, labels	=	cv.distanceTransformWithLabels(	src, distanceType, maskSize[, dst[, labels[, labelType]]]	)

Calculates the distance to the closest zero pixel for each pixel of the source image.

The function cv::distanceTransform calculates the approximate or precise distance from every binary image pixel to the nearest zero pixel. For zero image pixels, the distance will obviously be zero.

When maskSize == DIST_MASK_PRECISE and distanceType == DIST_L2 , the function runs the algorithm described in [57] . This algorithm is parallelized with the TBB library.

In other cases, the algorithm [19] is used. This means that for a pixel the function finds the shortest path to the nearest zero pixel consisting of basic shifts: horizontal, vertical, diagonal, or knight's move (the latest is available for a \(5\times 5\) mask). The overall distance is calculated as a sum of these basic distances. Since the distance function should be symmetric, all of the horizontal and vertical shifts must have the same cost (denoted as a ), all the diagonal shifts must have the same cost (denoted as b), and all knight's moves must have the same cost (denoted as c). For the DIST_C and DIST_L1 types, the distance is calculated precisely, whereas for DIST_L2 (Euclidean distance) the distance can be calculated only with a relative error (a \(5\times 5\) mask gives more accurate results). For a,b, and c, OpenCV uses the values suggested in the original paper:

• DIST_L1: a = 1, b = 2
• DIST_L2:
  • 3 x 3: a=0.955, b=1.3693
  • 5 x 5: a=1, b=1.4, c=2.1969
• DIST_C: a = 1, b = 1

Typically, for a fast, coarse distance estimation DIST_L2, a \(3\times 3\) mask is used. For a more accurate distance estimation DIST_L2, a \(5\times 5\) mask or the precise algorithm is used. Note that both the precise and the approximate algorithms are linear on the number of pixels.

This variant of the function does not only compute the minimum distance for each pixel \((x, y)\) but also identifies the nearest connected component consisting of zero pixels (labelType==DIST_LABEL_CCOMP) or the nearest zero pixel (labelType==DIST_LABEL_PIXEL). Index of the component/pixel is stored in labels(x, y). When labelType==DIST_LABEL_CCOMP, the function automatically finds connected components of zero pixels in the input image and marks them with distinct labels. When labelType==DIST_LABEL_CCOMP, the function scans through the input image and marks all the zero pixels with distinct labels.

In this mode, the complexity is still linear. That is, the function provides a very fast way to compute the Voronoi diagram for a binary image. Currently, the second variant can use only the approximate distance transform algorithm, i.e. maskSize=DIST_MASK_PRECISE is not supported yet.

Parameters

src	8-bit, single-channel (binary) source image.
dst	Output image with calculated distances. It is a 8-bit or 32-bit floating-point, single-channel image of the same size as src.
labels	Output 2D array of labels (the discrete Voronoi diagram). It has the type CV_32SC1 and the same size as src.
distanceType	Type of distance, see DistanceTypes
maskSize	Size of the distance transform mask, see DistanceTransformMasks. DIST_MASK_PRECISE is not supported by this variant. In case of the DIST_L1 or DIST_C distance type, the parameter is forced to 3 because a \(3\times 3\) mask gives the same result as \(5\times 5\) or any larger aperture.
labelType	Type of the label array to build, see DistanceTransformLabelTypes.

Examples:

samples/cpp/distrans.cpp.

distanceTransform() [2/2]

void cv::distanceTransform	(	InputArray	src,
		OutputArray	dst,
		int	distanceType,
		int	maskSize,
		int	dstType = CV_32F
	)

Python:
	dst	=	cv.distanceTransform(	src, distanceType, maskSize[, dst[, dstType]]	)
	dst, labels	=	cv.distanceTransformWithLabels(	src, distanceType, maskSize[, dst[, labels[, labelType]]]	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Parameters

src	8-bit, single-channel (binary) source image.
dst	Output image with calculated distances. It is a 8-bit or 32-bit floating-point, single-channel image of the same size as src .
distanceType	Type of distance, see DistanceTypes
maskSize	Size of the distance transform mask, see DistanceTransformMasks. In case of the DIST_L1 or DIST_C distance type, the parameter is forced to 3 because a \(3\times 3\) mask gives the same result as \(5\times 5\) or any larger aperture.
dstType	Type of output image. It can be CV_8U or CV_32F. Type CV_8U can be used only for the first variant of the function and distanceType == DIST_L1.

floodFill() [1/2]

int cv::floodFill	(	InputOutputArray	image,
		Point	seedPoint,
		Scalar	newVal,
		Rect *	rect = 0,
		Scalar	loDiff = Scalar(),
		Scalar	upDiff = Scalar(),
		int	flags = 4
	)

Python:
	retval, image, mask, rect	=	cv.floodFill(	image, mask, seedPoint, newVal[, loDiff[, upDiff[, flags]]]	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

variant without mask parameter

Examples:

samples/cpp/ffilldemo.cpp.

floodFill() [2/2]

int cv::floodFill	(	InputOutputArray	image,
		InputOutputArray	mask,
		Point	seedPoint,
		Scalar	newVal,
		Rect *	rect = 0,
		Scalar	loDiff = Scalar(),
		Scalar	upDiff = Scalar(),
		int	flags = 4
	)

Python:
	retval, image, mask, rect	=	cv.floodFill(	image, mask, seedPoint, newVal[, loDiff[, upDiff[, flags]]]	)

Fills a connected component with the given color.

The function cv::floodFill fills a connected component starting from the seed point with the specified color. The connectivity is determined by the color/brightness closeness of the neighbor pixels. The pixel at \((x,y)\) is considered to belong to the repainted domain if:

• in case of a grayscale image and floating range

  \[\texttt{src} (x',y')- \texttt{loDiff} \leq \texttt{src} (x,y) \leq \texttt{src} (x',y')+ \texttt{upDiff}\]

• in case of a grayscale image and fixed range

  \[\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)- \texttt{loDiff} \leq \texttt{src} (x,y) \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)+ \texttt{upDiff}\]

• in case of a color image and floating range

  \[\texttt{src} (x',y')_r- \texttt{loDiff} _r \leq \texttt{src} (x,y)_r \leq \texttt{src} (x',y')_r+ \texttt{upDiff} _r,\]

  \[\texttt{src} (x',y')_g- \texttt{loDiff} _g \leq \texttt{src} (x,y)_g \leq \texttt{src} (x',y')_g+ \texttt{upDiff} _g\]

  and

  \[\texttt{src} (x',y')_b- \texttt{loDiff} _b \leq \texttt{src} (x,y)_b \leq \texttt{src} (x',y')_b+ \texttt{upDiff} _b\]

• in case of a color image and fixed range

  \[\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_r- \texttt{loDiff} _r \leq \texttt{src} (x,y)_r \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_r+ \texttt{upDiff} _r,\]

  \[\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_g- \texttt{loDiff} _g \leq \texttt{src} (x,y)_g \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_g+ \texttt{upDiff} _g\]

  and

  \[\texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_b- \texttt{loDiff} _b \leq \texttt{src} (x,y)_b \leq \texttt{src} ( \texttt{seedPoint} .x, \texttt{seedPoint} .y)_b+ \texttt{upDiff} _b\]

where \(src(x',y')\) is the value of one of pixel neighbors that is already known to belong to the component. That is, to be added to the connected component, a color/brightness of the pixel should be close enough to:

• Color/brightness of one of its neighbors that already belong to the connected component in case of a floating range.
• Color/brightness of the seed point in case of a fixed range.

Use these functions to either mark a connected component with the specified color in-place, or build a mask and then extract the contour, or copy the region to another image, and so on.

Parameters

image	Input/output 1- or 3-channel, 8-bit, or floating-point image. It is modified by the function unless the FLOODFILL_MASK_ONLY flag is set in the second variant of the function. See the details below.
mask	Operation mask that should be a single-channel 8-bit image, 2 pixels wider and 2 pixels taller than image. Since this is both an input and output parameter, you must take responsibility of initializing it. Flood-filling cannot go across non-zero pixels in the input mask. For example, an edge detector output can be used as a mask to stop filling at edges. On output, pixels in the mask corresponding to filled pixels in the image are set to 1 or to the a value specified in flags as described below. Additionally, the function fills the border of the mask with ones to simplify internal processing. It is therefore possible to use the same mask in multiple calls to the function to make sure the filled areas do not overlap.
seedPoint	Starting point.
newVal	New value of the repainted domain pixels.
loDiff	Maximal lower brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component.
upDiff	Maximal upper brightness/color difference between the currently observed pixel and one of its neighbors belonging to the component, or a seed pixel being added to the component.
rect	Optional output parameter set by the function to the minimum bounding rectangle of the repainted domain.
flags	Operation flags. The first 8 bits contain a connectivity value. The default value of 4 means that only the four nearest neighbor pixels (those that share an edge) are considered. A connectivity value of 8 means that the eight nearest neighbor pixels (those that share a corner) will be considered. The next 8 bits (8-16) contain a value between 1 and 255 with which to fill the mask (the default value is 1). For example, 4 | ( 255 << 8 ) will consider 4 nearest neighbours and fill the mask with a value of 255. The following additional options occupy higher bits and therefore may be further combined with the connectivity and mask fill values using bit-wise or (|), see FloodFillFlags.

Note

Since the mask is larger than the filled image, a pixel \((x, y)\) in image corresponds to the pixel \((x+1, y+1)\) in the mask .

See also

findContours

grabCut()

void cv::grabCut	(	InputArray	img,
		InputOutputArray	mask,
		Rect	rect,
		InputOutputArray	bgdModel,
		InputOutputArray	fgdModel,
		int	iterCount,
		int	mode = GC_EVAL
	)

Python:
	mask, bgdModel, fgdModel	=	cv.grabCut(	img, mask, rect, bgdModel, fgdModel, iterCount[, mode]	)

Runs the GrabCut algorithm.

The function implements the GrabCut image segmentation algorithm.

Parameters

img	Input 8-bit 3-channel image.
mask	Input/output 8-bit single-channel mask. The mask is initialized by the function when mode is set to GC_INIT_WITH_RECT. Its elements may have one of the GrabCutClasses.
rect	ROI containing a segmented object. The pixels outside of the ROI are marked as "obvious background". The parameter is only used when mode==GC_INIT_WITH_RECT .
bgdModel	Temporary array for the background model. Do not modify it while you are processing the same image.
fgdModel	Temporary arrays for the foreground model. Do not modify it while you are processing the same image.
iterCount	Number of iterations the algorithm should make before returning the result. Note that the result can be refined with further calls with mode==GC_INIT_WITH_MASK or mode==GC_EVAL .
mode	Operation mode that could be one of the GrabCutModes

Examples:

samples/cpp/grabcut.cpp.

integral() [1/3]

void cv::integral	(	InputArray	src,
		OutputArray	sum,
		int	sdepth = -1
	)

Python:
	sum	=	cv.integral(	src[, sum[, sdepth]]	)
	sum, sqsum	=	cv.integral2(	src[, sum[, sqsum[, sdepth[, sqdepth]]]]	)
	sum, sqsum, tilted	=	cv.integral3(	src[, sum[, sqsum[, tilted[, sdepth[, sqdepth]]]]]	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

integral() [2/3]

void cv::integral	(	InputArray	src,
		OutputArray	sum,
		OutputArray	sqsum,
		int	sdepth = -1,
		int	sqdepth = -1
	)

Python:
	sum	=	cv.integral(	src[, sum[, sdepth]]	)
	sum, sqsum	=	cv.integral2(	src[, sum[, sqsum[, sdepth[, sqdepth]]]]	)
	sum, sqsum, tilted	=	cv.integral3(	src[, sum[, sqsum[, tilted[, sdepth[, sqdepth]]]]]	)

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

integral() [3/3]

void cv::integral	(	InputArray	src,
		OutputArray	sum,
		OutputArray	sqsum,
		OutputArray	tilted,
		int	sdepth = -1,
		int	sqdepth = -1
	)

Python:
	sum	=	cv.integral(	src[, sum[, sdepth]]	)
	sum, sqsum	=	cv.integral2(	src[, sum[, sqsum[, sdepth[, sqdepth]]]]	)
	sum, sqsum, tilted	=	cv.integral3(	src[, sum[, sqsum[, tilted[, sdepth[, sqdepth]]]]]	)

Calculates the integral of an image.

The function calculates one or more integral images for the source image as follows:

\[\texttt{sum} (X,Y) = \sum _{x<X,y<Y} \texttt{image} (x,y)\]

\[\texttt{sqsum} (X,Y) = \sum _{x<X,y<Y} \texttt{image} (x,y)^2\]

\[\texttt{tilted} (X,Y) = \sum _{y<Y,abs(x-X+1) \leq Y-y-1} \texttt{image} (x,y)\]

Using these integral images, you can calculate sum, mean, and standard deviation over a specific up-right or rotated rectangular region of the image in a constant time, for example:

\[\sum _{x_1 \leq x < x_2, \, y_1 \leq y < y_2} \texttt{image} (x,y) = \texttt{sum} (x_2,y_2)- \texttt{sum} (x_1,y_2)- \texttt{sum} (x_2,y_1)+ \texttt{sum} (x_1,y_1)\]

It makes possible to do a fast blurring or fast block correlation with a variable window size, for example. In case of multi-channel images, sums for each channel are accumulated independently.

As a practical example, the next figure shows the calculation of the integral of a straight rectangle Rect(3,3,3,2) and of a tilted rectangle Rect(5,1,2,3) . The selected pixels in the original image are shown, as well as the relative pixels in the integral images sum and tilted .

integral calculation example

Parameters

src	input image as \(W \times H\), 8-bit or floating-point (32f or 64f).
sum	integral image as \((W+1)\times (H+1)\) , 32-bit integer or floating-point (32f or 64f).
sqsum	integral image for squared pixel values; it is \((W+1)\times (H+1)\), double-precision floating-point (64f) array.
tilted	integral for the image rotated by 45 degrees; it is \((W+1)\times (H+1)\) array with the same data type as sum.
sdepth	desired depth of the integral and the tilted integral images, CV_32S, CV_32F, or CV_64F.
sqdepth	desired depth of the integral image of squared pixel values, CV_32F or CV_64F.

threshold()

double cv::threshold	(	InputArray	src,
		OutputArray	dst,
		double	thresh,
		double	maxval,
		int	type
	)

Python:
	retval, dst	=	cv.threshold(	src, thresh, maxval, type[, dst]	)

Applies a fixed-level threshold to each array element.

The function applies fixed-level thresholding to a multiple-channel array. The function is typically used to get a bi-level (binary) image out of a grayscale image ( compare could be also used for this purpose) or for removing a noise, that is, filtering out pixels with too small or too large values. There are several types of thresholding supported by the function. They are determined by type parameter.

Also, the special values THRESH_OTSU or THRESH_TRIANGLE may be combined with one of the above values. In these cases, the function determines the optimal threshold value using the Otsu's or Triangle algorithm and uses it instead of the specified thresh.

Note

Currently, the Otsu's and Triangle methods are implemented only for 8-bit single-channel images.

Parameters

src	input array (multiple-channel, 8-bit or 32-bit floating point).
dst	output array of the same size and type and the same number of channels as src.
thresh	threshold value.
maxval	maximum value to use with the THRESH_BINARY and THRESH_BINARY_INV thresholding types.
type	thresholding type (see ThresholdTypes).

Returns

the computed threshold value if Otsu's or Triangle methods used.

See also

adaptiveThreshold, findContours, compare, min, max

Examples:

samples/cpp/ffilldemo.cpp, samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp, and samples/tapi/squares.cpp.

watershed()

void cv::watershed	(	InputArray	image,
		InputOutputArray	markers
	)

Python:
	markers	=	cv.watershed(	image, markers	)

Performs a marker-based image segmentation using the watershed algorithm.

The function implements one of the variants of watershed, non-parametric marker-based segmentation algorithm, described in [137] .

Before passing the image to the function, you have to roughly outline the desired regions in the image markers with positive (>0) indices. So, every region is represented as one or more connected components with the pixel values 1, 2, 3, and so on. Such markers can be retrieved from a binary mask using findContours and drawContours (see the watershed.cpp demo). The markers are "seeds" of the future image regions. All the other pixels in markers , whose relation to the outlined regions is not known and should be defined by the algorithm, should be set to 0's. In the function output, each pixel in markers is set to a value of the "seed" components or to -1 at boundaries between the regions.

Note

Any two neighbor connected components are not necessarily separated by a watershed boundary (-1's pixels); for example, they can touch each other in the initial marker image passed to the function.

Parameters

image	Input 8-bit 3-channel image.
markers	Input/output 32-bit single-channel image (map) of markers. It should have the same size as image .

See also

findContours

Examples:

samples/cpp/watershed.cpp.