Color Transforms
This group contains algorithms dedicated to be applied on, or to produce, color images.
- ColorToLightness: Extracts the lightness plane of an RGB image in the HSL space.
- GetColorChannel: Extracts a given channel from a color image into a grayscale image.
- ColorToGrayscale: Separates a color image into its three grayscale components.
- GrayscaleToColor: Combines three grayscale input images into a single RGB output image.
- ColorSpaceConversion: Converts a color image from a color space to another one.
- ColorAntialiasing2d: Reduces color artifacts with a demosaicing algorithm.
- BayerToRgb2d: Applies a demosaicing algorithm on grayscale image with color meaning acquired with a Bayer filter camera.
- DecorrelationStretch2d: Enhances the color differences found in a color image.
- BlendAlphaChannelWithImage: Blends an RGBA input image with a background RGB image into an RGB output image.
- BlendAlphaChannelWithValue: Blends an RGBA input image with a padding color into an RGB output image.
When gray level images are not sufficient to solve an image processing problem, chromaticity
characteristics such as hue and saturation might help: color processing allows processing and analyzing the three
components of a true color image at the same time.
Color images are commonly represented by the RGB, HSL, or YIQ formats. An RGB image is composed of three components: the red, green, and blue channels.
In YIQ, the rgb, or rg chromaticity, space is obtained by normalizing the RGB components so that $r+g+b=1$. It removes intensity information, making it easier to localize an area based on chromaticity or saturation information.
Be aware that YIQ images are floating point images.
Color images are commonly represented by the RGB, HSL, or YIQ formats. An RGB image is composed of three components: the red, green, and blue channels.
RGB
Although the RGB basis is good for acquisition and display of color images, it is not always relevant to explain the perception of colors.HSL
An HSL image is composed of components expressing the hue, saturation, and luminance.- Hue refers to the color (red, orange, yellow, green, blue, purple).
- Saturation measures the lack of whiteness in a color ("fire engine" is saturated with red, while pink is desaturated).
- Luminance is an intensity measure and allows you to distinguish between light and dark.
YIQ
The YIQ format is largely used in broadcasting. The advantage of YIQ images is that the brightness component Y can be used alone by monochrome receivers, while still spanning the color space with the chromatic components I and Q.In YIQ, the rgb, or rg chromaticity, space is obtained by normalizing the RGB components so that $r+g+b=1$. It removes intensity information, making it easier to localize an area based on chromaticity or saturation information.
Color Functions
Most of the functions that work on gray level images will work on color images. The process is performed three times, once on each component.Be aware that YIQ images are floating point images.