OpenCV  4.0.0-pre
Open Source Computer Vision
Enumerations | Functions
ColorMaps in OpenCV

Enumerations

enum  cv::ColormapTypes {
  cv::COLORMAP_AUTUMN = 0,
  cv::COLORMAP_BONE = 1,
  cv::COLORMAP_JET = 2,
  cv::COLORMAP_WINTER = 3,
  cv::COLORMAP_RAINBOW = 4,
  cv::COLORMAP_OCEAN = 5,
  cv::COLORMAP_SUMMER = 6,
  cv::COLORMAP_SPRING = 7,
  cv::COLORMAP_COOL = 8,
  cv::COLORMAP_HSV = 9,
  cv::COLORMAP_PINK = 10,
  cv::COLORMAP_HOT = 11,
  cv::COLORMAP_PARULA = 12
}
 GNU Octave/MATLAB equivalent colormaps. More...
 

Functions

void cv::applyColorMap (InputArray src, OutputArray dst, int colormap)
 Applies a GNU Octave/MATLAB equivalent colormap on a given image. More...
 
void cv::applyColorMap (InputArray src, OutputArray dst, InputArray userColor)
 Applies a user colormap on a given image. More...
 

Detailed Description

The human perception isn't built for observing fine changes in grayscale images. Human eyes are more sensitive to observing changes between colors, so you often need to recolor your grayscale images to get a clue about them. OpenCV now comes with various colormaps to enhance the visualization in your computer vision application.

In OpenCV you only need applyColorMap to apply a colormap on a given image. The following sample code reads the path to an image from command line, applies a Jet colormap on it and shows the result:

#include <opencv2/core.hpp>
using namespace cv;
#include <iostream>
using namespace std;
int main(int argc, const char *argv[])
{
// We need an input image. (can be grayscale or color)
if (argc < 2)
{
cerr << "We need an image to process here. Please run: colorMap [path_to_image]" << endl;
return -1;
}
Mat img_in = imread(argv[1]);
if(img_in.empty())
{
cerr << "Sample image (" << argv[1] << ") is empty. Please adjust your path, so it points to a valid input image!" << endl;
return -1;
}
// Holds the colormap version of the image:
Mat img_color;
// Apply the colormap:
applyColorMap(img_in, img_color, COLORMAP_JET);
// Show the result:
imshow("colorMap", img_color);
waitKey(0);
return 0;
}
See also
ColormapTypes

Enumeration Type Documentation

§ ColormapTypes

GNU Octave/MATLAB equivalent colormaps.

Enumerator
COLORMAP_AUTUMN 
Python: cv.COLORMAP_AUTUMN
colorscale_autumn.jpg
autumn
COLORMAP_BONE 
Python: cv.COLORMAP_BONE
colorscale_bone.jpg
bone
COLORMAP_JET 
Python: cv.COLORMAP_JET
colorscale_jet.jpg
jet
COLORMAP_WINTER 
Python: cv.COLORMAP_WINTER
colorscale_winter.jpg
winter
COLORMAP_RAINBOW 
Python: cv.COLORMAP_RAINBOW
colorscale_rainbow.jpg
rainbow
COLORMAP_OCEAN 
Python: cv.COLORMAP_OCEAN
colorscale_ocean.jpg
ocean
COLORMAP_SUMMER 
Python: cv.COLORMAP_SUMMER
colorscale_summer.jpg
summer
COLORMAP_SPRING 
Python: cv.COLORMAP_SPRING
colorscale_spring.jpg
spring
COLORMAP_COOL 
Python: cv.COLORMAP_COOL
colorscale_cool.jpg
cool
COLORMAP_HSV 
Python: cv.COLORMAP_HSV
colorscale_hsv.jpg
HSV
COLORMAP_PINK 
Python: cv.COLORMAP_PINK
colorscale_pink.jpg
pink
COLORMAP_HOT 
Python: cv.COLORMAP_HOT
colorscale_hot.jpg
hot
COLORMAP_PARULA 
Python: cv.COLORMAP_PARULA
colorscale_parula.jpg
parula

Function Documentation

§ applyColorMap() [1/2]

void cv::applyColorMap ( InputArray  src,
OutputArray  dst,
int  colormap 
)
Python:
dst=cv.applyColorMap(src, colormap[, dst])
dst=cv.applyColorMap(src, userColor[, dst])

Applies a GNU Octave/MATLAB equivalent colormap on a given image.

Parameters
srcThe source image, grayscale or colored of type CV_8UC1 or CV_8UC3.
dstThe result is the colormapped source image. Note: Mat::create is called on dst.
colormapThe colormap to apply, see ColormapTypes
Examples:
samples/cpp/falsecolor.cpp.

§ applyColorMap() [2/2]

void cv::applyColorMap ( InputArray  src,
OutputArray  dst,
InputArray  userColor 
)
Python:
dst=cv.applyColorMap(src, colormap[, dst])
dst=cv.applyColorMap(src, userColor[, dst])

Applies a user colormap on a given image.

Parameters
srcThe source image, grayscale or colored of type CV_8UC1 or CV_8UC3.
dstThe result is the colormapped source image. Note: Mat::create is called on dst.
userColorThe colormap to apply of type CV_8UC1 or CV_8UC3 and size 256