Joe Verbout
opencv on mbed
ColorMaps in OpenCV
[Image processing]
The human perception isn't built for observing fine changes in grayscale images. More...
Enumerations | |
| enum | ColormapTypes { COLORMAP_AUTUMN = 0, COLORMAP_BONE = 1, COLORMAP_JET = 2, COLORMAP_WINTER = 3, COLORMAP_RAINBOW = 4, COLORMAP_OCEAN = 5, COLORMAP_SUMMER = 6, COLORMAP_SPRING = 7, COLORMAP_COOL = 8, COLORMAP_HSV = 9, COLORMAP_PINK = 10, COLORMAP_HOT = 11, COLORMAP_PARULA = 12 } |
GNU Octave/MATLAB equivalent colormaps. More... | |
Functions | |
| CV_EXPORTS_W void | applyColorMap (InputArray src, OutputArray dst, int colormap) |
| Applies a GNU Octave/MATLAB equivalent colormap on a given image. | |
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> #include <opencv2/imgproc.hpp> #include <opencv2/imgcodecs.hpp> #include <opencv2/highgui.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:
- cv::ColormapTypes
Enumeration Type Documentation
| enum ColormapTypes |
GNU Octave/MATLAB equivalent colormaps.
- Enumerator:
Definition at line 3780 of file imgproc.hpp.
Function Documentation
| CV_EXPORTS_W void cv::applyColorMap | ( | InputArray | src, |
| OutputArray | dst, | ||
| int | colormap | ||
| ) |
Applies a GNU Octave/MATLAB equivalent colormap on a given image.
- Parameters:
-
src The source image, grayscale or colored does not matter. dst The result is the colormapped source image. Note: Mat::create is called on dst. colormap The colormap to apply, see cv::ColormapTypes
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