OpenCV presentation series- part 2
- 1. OPENCV- COLORMAPS Standard types of colormaps in OpenCV-python
- 2. COLORMAPS • Color mapping is a function that maps the colors of one image to the colors of another image. • A color mapping may be referred to as the algorithm that results in the mapping function or the algorithm that transforms the image colors. • A colored image consists of three channels namely the Red, Green and Blue. • So the colormap function maps colors to the given RGB image. • Colormap is like a filter which uses gradients of different colors. • A colormap seen in the previous presentation is the HSV. • The HSV maps the temperature color for the RGB image.
- 3. COLORMAP IN OPENCV • The function used for the colormap is known as applyColorMap. • cv2.applyColorMap(image location, mode) • The first argument is the location of the read image. This is simply a variable which is used to store the read image from the cv2.imread function. • The second argument is the mode we are going to use. This refers to the type of colormap we are going to use. • This is done by calling the name of the colormap…like COLORMAP_BONE • This will use the bone type of colormap on the input image. • Also we have to use imshow and waitKey functions.
- 4. INDICES • The commands given in the mode argument are a bit longer. • So there are indices for each mode of colormap. • In python version of OpenCV there are about 22 different standard colormaps available. • These colormaps are indexed from 0 to 21. • For example, COLORMAP_AUTUMN has the index of 0. • So instead of typing the entire command, we can just type the index number for the respective colormap to access it. • The indices for the standard colormaps are given in the next slide.
- 5. STANDARD COLORMAPS 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,
- 6. CONTD… • COLORMAP_HOT = 11, COLORMAP_PARULA = 12, COLORMAP_MAGMA = 13, COLORMAP_INFERNO = 14, COLORMAP_PLASMA = 15, COLORMAP_VIRIDIS = 16, COLORMAP_CIVIDIS = 17, COLORMAP_TWILIGHT = 18, COLORMAP_TWILIGHT_SHIFTED = 19, COLORMAP_TURBO = 20, COLORMAP_DEEPGREEN = 21
- 9. COLORMAP_JET
- 10. COLORMAP_WINTER
- 11. COLORMAP_RAINBOW
- 12. COLRMAP_OCEAN
- 13. COLORMAP_SUMMER
- 14. COLORMAP_SPRING
- 15. COLORMAP_COOL
- 16. COLORMAP_HSV
- 17. COLORMAP_PINK
- 18. COLORMAP_HOT
- 19. COLORMAP_PARULA
- 20. COLORMAP_MAGMA
- 21. COLORMAP_INFERNO
- 22. COLORMAP_PLASMA
- 23. COLORMAP_VIRIDIS
- 24. COLORMAP_CIVIDIS
- 27. COLORMAP_TURBO