Package org.opencv.imgcodecs

Class Imgcodecs

  • public class Imgcodecs
extends java.lang.Object

    • Field Detail

      • IMREAD_REDUCED_GRAYSCALE_2

        public static final int IMREAD_REDUCED_GRAYSCALE_2
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      • IMREAD_REDUCED_GRAYSCALE_4

        public static final int IMREAD_REDUCED_GRAYSCALE_4
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      • IMREAD_REDUCED_GRAYSCALE_8

        public static final int IMREAD_REDUCED_GRAYSCALE_8
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      • IMREAD_IGNORE_ORIENTATION

        public static final int IMREAD_IGNORE_ORIENTATION
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      • IMWRITE_EXR_COMPRESSION_NO

        public static final int IMWRITE_EXR_COMPRESSION_NO
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      • IMWRITE_EXR_COMPRESSION_RLE

        public static final int IMWRITE_EXR_COMPRESSION_RLE
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      • IMWRITE_EXR_COMPRESSION_ZIPS

        public static final int IMWRITE_EXR_COMPRESSION_ZIPS
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      • IMWRITE_EXR_COMPRESSION_ZIP

        public static final int IMWRITE_EXR_COMPRESSION_ZIP
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      • IMWRITE_EXR_COMPRESSION_PIZ

        public static final int IMWRITE_EXR_COMPRESSION_PIZ
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      • IMWRITE_EXR_COMPRESSION_PXR24

        public static final int IMWRITE_EXR_COMPRESSION_PXR24
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      • IMWRITE_EXR_COMPRESSION_B44

        public static final int IMWRITE_EXR_COMPRESSION_B44
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      • IMWRITE_EXR_COMPRESSION_B44A

        public static final int IMWRITE_EXR_COMPRESSION_B44A
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      • IMWRITE_EXR_COMPRESSION_DWAA

        public static final int IMWRITE_EXR_COMPRESSION_DWAA
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      • IMWRITE_EXR_COMPRESSION_DWAB

        public static final int IMWRITE_EXR_COMPRESSION_DWAB
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      • IMWRITE_JPEG_PROGRESSIVE

        public static final int IMWRITE_JPEG_PROGRESSIVE
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      • IMWRITE_JPEG_RST_INTERVAL

        public static final int IMWRITE_JPEG_RST_INTERVAL
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      • IMWRITE_JPEG_LUMA_QUALITY

        public static final int IMWRITE_JPEG_LUMA_QUALITY
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      • IMWRITE_JPEG_CHROMA_QUALITY

        public static final int IMWRITE_JPEG_CHROMA_QUALITY
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      • IMWRITE_JPEG_SAMPLING_FACTOR

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR
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      • IMWRITE_PNG_COMPRESSION

        public static final int IMWRITE_PNG_COMPRESSION
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      • IMWRITE_EXR_COMPRESSION

        public static final int IMWRITE_EXR_COMPRESSION
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      • IMWRITE_EXR_DWA_COMPRESSION_LEVEL

        public static final int IMWRITE_EXR_DWA_COMPRESSION_LEVEL
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      • IMWRITE_HDR_COMPRESSION

        public static final int IMWRITE_HDR_COMPRESSION
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      • IMWRITE_TIFF_COMPRESSION

        public static final int IMWRITE_TIFF_COMPRESSION
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      • IMWRITE_TIFF_ROWSPERSTRIP

        public static final int IMWRITE_TIFF_ROWSPERSTRIP
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      • IMWRITE_JPEG2000_COMPRESSION_X1000

        public static final int IMWRITE_JPEG2000_COMPRESSION_X1000
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      • IMWRITE_HDR_COMPRESSION_NONE

        public static final int IMWRITE_HDR_COMPRESSION_NONE
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      • IMWRITE_HDR_COMPRESSION_RLE

        public static final int IMWRITE_HDR_COMPRESSION_RLE
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      • IMWRITE_JPEG_SAMPLING_FACTOR_411

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR_411
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      • IMWRITE_JPEG_SAMPLING_FACTOR_420

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR_420
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      • IMWRITE_JPEG_SAMPLING_FACTOR_422

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR_422
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      • IMWRITE_JPEG_SAMPLING_FACTOR_440

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR_440
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      • IMWRITE_JPEG_SAMPLING_FACTOR_444

        public static final int IMWRITE_JPEG_SAMPLING_FACTOR_444
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      • IMWRITE_PAM_FORMAT_NULL

        public static final int IMWRITE_PAM_FORMAT_NULL
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      • IMWRITE_PAM_FORMAT_BLACKANDWHITE

        public static final int IMWRITE_PAM_FORMAT_BLACKANDWHITE
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      • IMWRITE_PAM_FORMAT_GRAYSCALE

        public static final int IMWRITE_PAM_FORMAT_GRAYSCALE
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      • IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA

        public static final int IMWRITE_PAM_FORMAT_GRAYSCALE_ALPHA
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      • IMWRITE_PAM_FORMAT_RGB_ALPHA

        public static final int IMWRITE_PAM_FORMAT_RGB_ALPHA
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      • IMWRITE_PNG_STRATEGY_DEFAULT

        public static final int IMWRITE_PNG_STRATEGY_DEFAULT
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      • IMWRITE_PNG_STRATEGY_FILTERED

        public static final int IMWRITE_PNG_STRATEGY_FILTERED
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      • IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY

        public static final int IMWRITE_PNG_STRATEGY_HUFFMAN_ONLY
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      • IMWRITE_PNG_STRATEGY_RLE

        public static final int IMWRITE_PNG_STRATEGY_RLE
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      • IMWRITE_PNG_STRATEGY_FIXED

        public static final int IMWRITE_PNG_STRATEGY_FIXED
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      • IMWRITE_TIFF_COMPRESSION_NONE

        public static final int IMWRITE_TIFF_COMPRESSION_NONE
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      • IMWRITE_TIFF_COMPRESSION_CCITTRLE

        public static final int IMWRITE_TIFF_COMPRESSION_CCITTRLE
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      • IMWRITE_TIFF_COMPRESSION_CCITTFAX3

        public static final int IMWRITE_TIFF_COMPRESSION_CCITTFAX3
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      • IMWRITE_TIFF_COMPRESSION_CCITT_T4

        public static final int IMWRITE_TIFF_COMPRESSION_CCITT_T4
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      • IMWRITE_TIFF_COMPRESSION_CCITTFAX4

        public static final int IMWRITE_TIFF_COMPRESSION_CCITTFAX4
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      • IMWRITE_TIFF_COMPRESSION_CCITT_T6

        public static final int IMWRITE_TIFF_COMPRESSION_CCITT_T6
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      • IMWRITE_TIFF_COMPRESSION_LZW

        public static final int IMWRITE_TIFF_COMPRESSION_LZW
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      • IMWRITE_TIFF_COMPRESSION_OJPEG

        public static final int IMWRITE_TIFF_COMPRESSION_OJPEG
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      • IMWRITE_TIFF_COMPRESSION_JPEG

        public static final int IMWRITE_TIFF_COMPRESSION_JPEG
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      • IMWRITE_TIFF_COMPRESSION_T85

        public static final int IMWRITE_TIFF_COMPRESSION_T85
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      • IMWRITE_TIFF_COMPRESSION_T43

        public static final int IMWRITE_TIFF_COMPRESSION_T43
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      • IMWRITE_TIFF_COMPRESSION_NEXT

        public static final int IMWRITE_TIFF_COMPRESSION_NEXT
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      • IMWRITE_TIFF_COMPRESSION_CCITTRLEW

        public static final int IMWRITE_TIFF_COMPRESSION_CCITTRLEW
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      • IMWRITE_TIFF_COMPRESSION_PACKBITS

        public static final int IMWRITE_TIFF_COMPRESSION_PACKBITS
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      • IMWRITE_TIFF_COMPRESSION_THUNDERSCAN

        public static final int IMWRITE_TIFF_COMPRESSION_THUNDERSCAN
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      • IMWRITE_TIFF_COMPRESSION_IT8CTPAD

        public static final int IMWRITE_TIFF_COMPRESSION_IT8CTPAD
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      • IMWRITE_TIFF_COMPRESSION_IT8LW

        public static final int IMWRITE_TIFF_COMPRESSION_IT8LW
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      • IMWRITE_TIFF_COMPRESSION_IT8MP

        public static final int IMWRITE_TIFF_COMPRESSION_IT8MP
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      • IMWRITE_TIFF_COMPRESSION_IT8BL

        public static final int IMWRITE_TIFF_COMPRESSION_IT8BL
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      • IMWRITE_TIFF_COMPRESSION_PIXARFILM

        public static final int IMWRITE_TIFF_COMPRESSION_PIXARFILM
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      • IMWRITE_TIFF_COMPRESSION_PIXARLOG

        public static final int IMWRITE_TIFF_COMPRESSION_PIXARLOG
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      • IMWRITE_TIFF_COMPRESSION_DEFLATE

        public static final int IMWRITE_TIFF_COMPRESSION_DEFLATE
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      • IMWRITE_TIFF_COMPRESSION_ADOBE_DEFLATE

        public static final int IMWRITE_TIFF_COMPRESSION_ADOBE_DEFLATE
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      • IMWRITE_TIFF_COMPRESSION_DCS

        public static final int IMWRITE_TIFF_COMPRESSION_DCS
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      • IMWRITE_TIFF_COMPRESSION_JBIG

        public static final int IMWRITE_TIFF_COMPRESSION_JBIG
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      • IMWRITE_TIFF_COMPRESSION_SGILOG

        public static final int IMWRITE_TIFF_COMPRESSION_SGILOG
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      • IMWRITE_TIFF_COMPRESSION_SGILOG24

        public static final int IMWRITE_TIFF_COMPRESSION_SGILOG24
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      • IMWRITE_TIFF_COMPRESSION_JP2000

        public static final int IMWRITE_TIFF_COMPRESSION_JP2000
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      • IMWRITE_TIFF_COMPRESSION_LERC

        public static final int IMWRITE_TIFF_COMPRESSION_LERC
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      • IMWRITE_TIFF_COMPRESSION_LZMA

        public static final int IMWRITE_TIFF_COMPRESSION_LZMA
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      • IMWRITE_TIFF_COMPRESSION_ZSTD

        public static final int IMWRITE_TIFF_COMPRESSION_ZSTD
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      • IMWRITE_TIFF_COMPRESSION_WEBP

        public static final int IMWRITE_TIFF_COMPRESSION_WEBP
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      • IMWRITE_TIFF_COMPRESSION_JXL

        public static final int IMWRITE_TIFF_COMPRESSION_JXL
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      • IMWRITE_TIFF_PREDICTOR_NONE

        public static final int IMWRITE_TIFF_PREDICTOR_NONE
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      • IMWRITE_TIFF_PREDICTOR_HORIZONTAL

        public static final int IMWRITE_TIFF_PREDICTOR_HORIZONTAL
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      • IMWRITE_TIFF_PREDICTOR_FLOATINGPOINT

        public static final int IMWRITE_TIFF_PREDICTOR_FLOATINGPOINT
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    • Constructor Detail

      • Imgcodecs

        public Imgcodecs()

    • Method Detail

      • imread

        public static Mat imread​(java.lang.String filename,
                         int flags)
        Loads an image from a file. imread The imread function loads an image from the specified file and returns OpenCV matrix. If the image cannot be read (because of a missing file, improper permissions, or unsupported/invalid format), the function returns an empty matrix. Currently, the following file formats are supported:
        • Windows bitmaps - \*.bmp, \*.dib (always supported)
        • JPEG files - \*.jpeg, \*.jpg, \*.jpe (see the *Note* section)
        • JPEG 2000 files - \*.jp2 (see the *Note* section)
        • Portable Network Graphics - \*.png (see the *Note* section)
        • WebP - \*.webp (see the *Note* section)
        • AVIF - \*.avif (see the *Note* section)
        • Portable image format - \*.pbm, \*.pgm, \*.ppm, \*.pxm, \*.pnm (always supported)
        • PFM files - \*.pfm (see the *Note* section)
        • Sun rasters - \*.sr, \*.ras (always supported)
        • TIFF files - \*.tiff, \*.tif (see the *Note* section)
        • OpenEXR Image files - \*.exr (see the *Note* section)
        • Radiance HDR - \*.hdr, \*.pic (always supported)
        • Raster and Vector geospatial data supported by GDAL (see the *Note* section)
        Note:
        • The function determines the type of an image by its content, not by the file extension.
        • In the case of color images, the decoded images will have the channels stored in B G R order.
        • When using IMREAD_GRAYSCALE, the codec's internal grayscale conversion will be used, if available. Results may differ from the output of cvtColor().
        • On Microsoft Windows\* and Mac OS\*, the codecs shipped with OpenCV (libjpeg, libpng, libtiff, and libjasper) are used by default. So, OpenCV can always read JPEGs, PNGs, and TIFFs. On Mac OS, there is also an option to use native Mac OS image readers. However, beware that currently these native image loaders give images with different pixel values because of the color management embedded into Mac OS.
        • On Linux\*, BSD flavors, and other Unix-like open-source operating systems, OpenCV looks for codecs supplied with the OS. Ensure the relevant packages are installed (including development files, such as "libjpeg-dev" in Debian\* and Ubuntu\*) to get codec support, or turn on the OPENCV_BUILD_3RDPARTY_LIBS flag in CMake.
        • If the *WITH_GDAL* flag is set to true in CMake and REF: IMREAD_LOAD_GDAL is used to load the image, the [GDAL](http://www.gdal.org) driver will be used to decode the image, supporting [Raster](http://www.gdal.org/formats_list.html) and [Vector](http://www.gdal.org/ogr_formats.html) formats.
        • If EXIF information is embedded in the image file, the EXIF orientation will be taken into account, and thus the image will be rotated accordingly unless the flags REF: IMREAD_IGNORE_ORIENTATION or REF: IMREAD_UNCHANGED are passed.
        • Use the IMREAD_UNCHANGED flag to preserve the floating-point values from PFM images.
        • By default, the number of pixels must be less than 2^30. This limit can be changed by setting the environment variable OPENCV_IO_MAX_IMAGE_PIXELS. See REF: tutorial_env_reference.
        Parameters:
        filename - Name of the file to be loaded.
        flags - Flag that can take values of cv::ImreadModes.
        Returns:
        automatically generated

      • imread

        public static Mat imread​(java.lang.String filename)
        Loads an image from a file. imread The imread function loads an image from the specified file and returns OpenCV matrix. If the image cannot be read (because of a missing file, improper permissions, or unsupported/invalid format), the function returns an empty matrix. Currently, the following file formats are supported:
        • Windows bitmaps - \*.bmp, \*.dib (always supported)
        • JPEG files - \*.jpeg, \*.jpg, \*.jpe (see the *Note* section)
        • JPEG 2000 files - \*.jp2 (see the *Note* section)
        • Portable Network Graphics - \*.png (see the *Note* section)
        • WebP - \*.webp (see the *Note* section)
        • AVIF - \*.avif (see the *Note* section)
        • Portable image format - \*.pbm, \*.pgm, \*.ppm, \*.pxm, \*.pnm (always supported)
        • PFM files - \*.pfm (see the *Note* section)
        • Sun rasters - \*.sr, \*.ras (always supported)
        • TIFF files - \*.tiff, \*.tif (see the *Note* section)
        • OpenEXR Image files - \*.exr (see the *Note* section)
        • Radiance HDR - \*.hdr, \*.pic (always supported)
        • Raster and Vector geospatial data supported by GDAL (see the *Note* section)
        Note:
        • The function determines the type of an image by its content, not by the file extension.
        • In the case of color images, the decoded images will have the channels stored in B G R order.
        • When using IMREAD_GRAYSCALE, the codec's internal grayscale conversion will be used, if available. Results may differ from the output of cvtColor().
        • On Microsoft Windows\* and Mac OS\*, the codecs shipped with OpenCV (libjpeg, libpng, libtiff, and libjasper) are used by default. So, OpenCV can always read JPEGs, PNGs, and TIFFs. On Mac OS, there is also an option to use native Mac OS image readers. However, beware that currently these native image loaders give images with different pixel values because of the color management embedded into Mac OS.
        • On Linux\*, BSD flavors, and other Unix-like open-source operating systems, OpenCV looks for codecs supplied with the OS. Ensure the relevant packages are installed (including development files, such as "libjpeg-dev" in Debian\* and Ubuntu\*) to get codec support, or turn on the OPENCV_BUILD_3RDPARTY_LIBS flag in CMake.
        • If the *WITH_GDAL* flag is set to true in CMake and REF: IMREAD_LOAD_GDAL is used to load the image, the [GDAL](http://www.gdal.org) driver will be used to decode the image, supporting [Raster](http://www.gdal.org/formats_list.html) and [Vector](http://www.gdal.org/ogr_formats.html) formats.
        • If EXIF information is embedded in the image file, the EXIF orientation will be taken into account, and thus the image will be rotated accordingly unless the flags REF: IMREAD_IGNORE_ORIENTATION or REF: IMREAD_UNCHANGED are passed.
        • Use the IMREAD_UNCHANGED flag to preserve the floating-point values from PFM images.
        • By default, the number of pixels must be less than 2^30. This limit can be changed by setting the environment variable OPENCV_IO_MAX_IMAGE_PIXELS. See REF: tutorial_env_reference.
        Parameters:
        filename - Name of the file to be loaded.
        Returns:
        automatically generated

      • imread

        public static void imread​(java.lang.String filename,
                          Mat dst,
                          int flags)
        Loads an image from a file. This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts and the return value.
        Parameters:
        filename - Name of file to be loaded.
        dst - object in which the image will be loaded.
        flags - Flag that can take values of cv::ImreadModes Note: The image passing through the img parameter can be pre-allocated. The memory is reused if the shape and the type match with the load image.

      • imread

        public static void imread​(java.lang.String filename,
                          Mat dst)
        Loads an image from a file. This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts and the return value.
        Parameters:
        filename - Name of file to be loaded.
        dst - object in which the image will be loaded. Note: The image passing through the img parameter can be pre-allocated. The memory is reused if the shape and the type match with the load image.

      • imreadmulti

        public static boolean imreadmulti​(java.lang.String filename,
                                  java.util.List<Mat> mats,
                                  int flags)
        Loads a multi-page image from a file. The function imreadmulti loads a multi-page image from the specified file into a vector of Mat objects.
        Parameters:
        filename - Name of file to be loaded.
        mats - A vector of Mat objects holding each page.
        flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR. SEE: cv::imread
        Returns:
        automatically generated

      • imreadmulti

        public static boolean imreadmulti​(java.lang.String filename,
                                  java.util.List<Mat> mats)
        Loads a multi-page image from a file. The function imreadmulti loads a multi-page image from the specified file into a vector of Mat objects.
        Parameters:
        filename - Name of file to be loaded.
        mats - A vector of Mat objects holding each page. SEE: cv::imread
        Returns:
        automatically generated

      • imreadmulti

        public static boolean imreadmulti​(java.lang.String filename,
                                  java.util.List<Mat> mats,
                                  int start,
                                  int count,
                                  int flags)
        Loads images of a multi-page image from a file. The function imreadmulti loads a specified range from a multi-page image from the specified file into a vector of Mat objects.
        Parameters:
        filename - Name of file to be loaded.
        mats - A vector of Mat objects holding each page.
        start - Start index of the image to load
        count - Count number of images to load
        flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR. SEE: cv::imread
        Returns:
        automatically generated

      • imreadmulti

        public static boolean imreadmulti​(java.lang.String filename,
                                  java.util.List<Mat> mats,
                                  int start,
                                  int count)
        Loads images of a multi-page image from a file. The function imreadmulti loads a specified range from a multi-page image from the specified file into a vector of Mat objects.
        Parameters:
        filename - Name of file to be loaded.
        mats - A vector of Mat objects holding each page.
        start - Start index of the image to load
        count - Count number of images to load SEE: cv::imread
        Returns:
        automatically generated

      • imcount

        public static long imcount​(java.lang.String filename,
                           int flags)
        Returns the number of images inside the given file The function imcount returns the number of pages in a multi-page image (e.g. TIFF), the number of frames in an animation (e.g. AVIF), and 1 otherwise. If the image cannot be decoded, 0 is returned.
        Parameters:
        filename - Name of file to be loaded.
        flags - Flag that can take values of cv::ImreadModes, default with cv::IMREAD_ANYCOLOR. TODO: when cv::IMREAD_LOAD_GDAL flag used the return value will be 0 or 1 because OpenCV's GDAL decoder doesn't support multi-page reading yet.
        Returns:
        automatically generated

      • imcount

        public static long imcount​(java.lang.String filename)
        Returns the number of images inside the given file The function imcount returns the number of pages in a multi-page image (e.g. TIFF), the number of frames in an animation (e.g. AVIF), and 1 otherwise. If the image cannot be decoded, 0 is returned.
        Parameters:
        filename - Name of file to be loaded. TODO: when cv::IMREAD_LOAD_GDAL flag used the return value will be 0 or 1 because OpenCV's GDAL decoder doesn't support multi-page reading yet.
        Returns:
        automatically generated

      • imwrite

        public static boolean imwrite​(java.lang.String filename,
                              Mat img,
                              MatOfInt params)
        Saves an image to a specified file. The function imwrite saves the image to the specified file. The image format is chosen based on the filename extension (see cv::imread for the list of extensions). In general, only 8-bit unsigned (CV_8U) single-channel or 3-channel (with 'BGR' channel order) images can be saved using this function, with these exceptions:
        • With OpenEXR encoder, only 32-bit float (CV_32F) images can be saved.
          • 8-bit unsigned (CV_8U) images are not supported.
        • With Radiance HDR encoder, non 64-bit float (CV_64F) images can be saved.
          • All images will be converted to 32-bit float (CV_32F).
        • With JPEG 2000 encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With PAM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With PNG encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
          • PNG images with an alpha channel can be saved using this function. To do this, create 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).
        • With PGM/PPM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With TIFF encoder, 8-bit unsigned (CV_8U), 16-bit unsigned (CV_16U), 32-bit float (CV_32F) and 64-bit float (CV_64F) images can be saved.
          • Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below).
          • 32-bit float 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel)
          If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way.
        If the format, depth or channel order is different, use Mat::convertTo and cv::cvtColor to convert it before saving. Or, use the universal FileStorage I/O functions to save the image to XML or YAML format. The sample below shows how to create a BGRA image, how to set custom compression parameters and save it to a PNG file. It also demonstrates how to save multiple images in a TIFF file: INCLUDE: snippets/imgcodecs_imwrite.cpp
        Parameters:
        filename - Name of the file.
        img - (Mat or vector of Mat) Image or Images to be saved.
        params - Format-specific parameters encoded as pairs (paramId_1, paramValue_1, paramId_2, paramValue_2, ... .) see cv::ImwriteFlags
        Returns:
        automatically generated

      • imwrite

        public static boolean imwrite​(java.lang.String filename,
                              Mat img)
        Saves an image to a specified file. The function imwrite saves the image to the specified file. The image format is chosen based on the filename extension (see cv::imread for the list of extensions). In general, only 8-bit unsigned (CV_8U) single-channel or 3-channel (with 'BGR' channel order) images can be saved using this function, with these exceptions:
        • With OpenEXR encoder, only 32-bit float (CV_32F) images can be saved.
          • 8-bit unsigned (CV_8U) images are not supported.
        • With Radiance HDR encoder, non 64-bit float (CV_64F) images can be saved.
          • All images will be converted to 32-bit float (CV_32F).
        • With JPEG 2000 encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With PAM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With PNG encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
          • PNG images with an alpha channel can be saved using this function. To do this, create 8-bit (or 16-bit) 4-channel image BGRA, where the alpha channel goes last. Fully transparent pixels should have alpha set to 0, fully opaque pixels should have alpha set to 255/65535 (see the code sample below).
        • With PGM/PPM encoder, 8-bit unsigned (CV_8U) and 16-bit unsigned (CV_16U) images can be saved.
        • With TIFF encoder, 8-bit unsigned (CV_8U), 16-bit unsigned (CV_16U), 32-bit float (CV_32F) and 64-bit float (CV_64F) images can be saved.
          • Multiple images (vector of Mat) can be saved in TIFF format (see the code sample below).
          • 32-bit float 3-channel (CV_32FC3) TIFF images will be saved using the LogLuv high dynamic range encoding (4 bytes per pixel)
          If the image format is not supported, the image will be converted to 8-bit unsigned (CV_8U) and saved that way.
        If the format, depth or channel order is different, use Mat::convertTo and cv::cvtColor to convert it before saving. Or, use the universal FileStorage I/O functions to save the image to XML or YAML format. The sample below shows how to create a BGRA image, how to set custom compression parameters and save it to a PNG file. It also demonstrates how to save multiple images in a TIFF file: INCLUDE: snippets/imgcodecs_imwrite.cpp
        Parameters:
        filename - Name of the file.
        img - (Mat or vector of Mat) Image or Images to be saved.
        Returns:
        automatically generated

      • imwritemulti

        public static boolean imwritemulti​(java.lang.String filename,
                                   java.util.List<Mat> img,
                                   MatOfInt params)

      • imwritemulti

        public static boolean imwritemulti​(java.lang.String filename,
                                   java.util.List<Mat> img)

      • imdecode

        public static Mat imdecode​(Mat buf,
                           int flags)
        Reads an image from a buffer in memory. The function imdecode reads an image from the specified buffer in the memory. If the buffer is too short or contains invalid data, the function returns an empty matrix ( Mat::data==NULL ). See cv::imread for the list of supported formats and flags description. Note: In the case of color images, the decoded images will have the channels stored in B G R order.
        Parameters:
        buf - Input array or vector of bytes.
        flags - The same flags as in cv::imread, see cv::ImreadModes.
        Returns:
        automatically generated

      • imdecodemulti

        public static boolean imdecodemulti​(Mat buf,
                                    int flags,
                                    java.util.List<Mat> mats,
                                    Range range)
        Reads a multi-page image from a buffer in memory. The function imdecodemulti reads a multi-page image from the specified buffer in the memory. If the buffer is too short or contains invalid data, the function returns false. See cv::imreadmulti for the list of supported formats and flags description. Note: In the case of color images, the decoded images will have the channels stored in B G R order.
        Parameters:
        buf - Input array or vector of bytes.
        flags - The same flags as in cv::imread, see cv::ImreadModes.
        mats - A vector of Mat objects holding each page, if more than one.
        range - A continuous selection of pages.
        Returns:
        automatically generated

      • imdecodemulti

        public static boolean imdecodemulti​(Mat buf,
                                    int flags,
                                    java.util.List<Mat> mats)
        Reads a multi-page image from a buffer in memory. The function imdecodemulti reads a multi-page image from the specified buffer in the memory. If the buffer is too short or contains invalid data, the function returns false. See cv::imreadmulti for the list of supported formats and flags description. Note: In the case of color images, the decoded images will have the channels stored in B G R order.
        Parameters:
        buf - Input array or vector of bytes.
        flags - The same flags as in cv::imread, see cv::ImreadModes.
        mats - A vector of Mat objects holding each page, if more than one.
        Returns:
        automatically generated

      • imencode

        public static boolean imencode​(java.lang.String ext,
                               Mat img,
                               MatOfByte buf,
                               MatOfInt params)
        Encodes an image into a memory buffer. The function imencode compresses the image and stores it in the memory buffer that is resized to fit the result. See cv::imwrite for the list of supported formats and flags description.
        Parameters:
        ext - File extension that defines the output format. Must include a leading period.
        img - Image to be compressed.
        buf - Output buffer resized to fit the compressed image.
        params - Format-specific parameters. See cv::imwrite and cv::ImwriteFlags.
        Returns:
        automatically generated

      • imencode

        public static boolean imencode​(java.lang.String ext,
                               Mat img,
                               MatOfByte buf)
        Encodes an image into a memory buffer. The function imencode compresses the image and stores it in the memory buffer that is resized to fit the result. See cv::imwrite for the list of supported formats and flags description.
        Parameters:
        ext - File extension that defines the output format. Must include a leading period.
        img - Image to be compressed.
        buf - Output buffer resized to fit the compressed image.
        Returns:
        automatically generated

      • imencodemulti

        public static boolean imencodemulti​(java.lang.String ext,
                                    java.util.List<Mat> imgs,
                                    MatOfByte buf,
                                    MatOfInt params)
        Encodes array of images into a memory buffer. The function is analog to cv::imencode for in-memory multi-page image compression. See cv::imwrite for the list of supported formats and flags description.
        Parameters:
        ext - File extension that defines the output format. Must include a leading period.
        imgs - Vector of images to be written.
        buf - Output buffer resized to fit the compressed data.
        params - Format-specific parameters. See cv::imwrite and cv::ImwriteFlags.
        Returns:
        automatically generated

      • imencodemulti

        public static boolean imencodemulti​(java.lang.String ext,
                                    java.util.List<Mat> imgs,
                                    MatOfByte buf)
        Encodes array of images into a memory buffer. The function is analog to cv::imencode for in-memory multi-page image compression. See cv::imwrite for the list of supported formats and flags description.
        Parameters:
        ext - File extension that defines the output format. Must include a leading period.
        imgs - Vector of images to be written.
        buf - Output buffer resized to fit the compressed data.
        Returns:
        automatically generated

      • haveImageReader

        public static boolean haveImageReader​(java.lang.String filename)
        Checks if the specified image file can be decoded by OpenCV. The function haveImageReader checks if OpenCV is capable of reading the specified file. This can be useful for verifying support for a given image format before attempting to load an image.
        Parameters:
        filename - The name of the file to be checked.
        Returns:
        true if an image reader for the specified file is available and the file can be opened, false otherwise. Note: The function checks the availability of image codecs that are either built into OpenCV or dynamically loaded. It does not check for the actual existence of the file but rather the ability to read the specified file type. If the file cannot be opened or the format is unsupported, the function will return false. SEE: cv::haveImageWriter, cv::imread, cv::imdecode

      • haveImageWriter

        public static boolean haveImageWriter​(java.lang.String filename)
        Checks if the specified image file or specified file extension can be encoded by OpenCV. The function haveImageWriter checks if OpenCV is capable of writing images with the specified file extension. This can be useful for verifying support for a given image format before attempting to save an image.
        Parameters:
        filename - The name of the file or the file extension (e.g., ".jpg", ".png"). It is recommended to provide the file extension rather than the full file name.
        Returns:
        true if an image writer for the specified extension is available, false otherwise. Note: The function checks the availability of image codecs that are either built into OpenCV or dynamically loaded. It does not check for the actual existence of the file but rather the ability to write files of the given type. SEE: cv::haveImageReader, cv::imwrite, cv::imencode