RGB and HSI of Image color space

Depending on the color-aware angle, the color space can be divided into the following 3 categories.

1) mixed color space : The color is synthesized by the proportions of the 3 base colors. For example, color spaces such as RGB,CMY (K) and XYZ belong to this type.

2) non- linear luminance / chroma color space : This color space is characterized by a component representation of non-color perception, with two independent components to represent the perception of color. Such a system is convenient when black and white images are required. For example, YUV and so on.

3) intensity / saturation / hue color space : describes the perception of color with saturation and chroma, which makes the interpretation of color more intuitive, It is also useful to eliminate the effects of light. For example, HSV, HSL, and so on.

RGB color model for a cube in the Centica coordinate system, R, G, and B represent 3 axes respectively. When R, G, b corresponds to the value of 0 o'clock, that is, the origin of the coordinates, the black is indicated. Conversely when R. G. b corresponds to the value of the maximum value is indicated by the white. Other points in the cube space represent other colors. 16777216 colors can be represented when the value range of 3 components is an integer between 0-255.

HSI uses hue (hue), saturation (saturation or chroma), and intensity (Intensity) to describe color.

Hue is a property that describes a solid color, which reflects the nature of the color. The effect of saturation is to give a solid color is diluted by the degree of intensity is the brightness of the color, the value range from 0% (black) to 100% (the brightest). intensity also refers to lightness (luminance) or brightness (lightness) intensity is the most powerful and most effective way to describe a monochrome image, its advantage is that it is measurable and easy to explain.

The study found that people's visual sensitivity to brightness is far stronger than 10 of the sensitivity of the color shade, so the HSI color space than the RGB color space more in line with human visual characteristics.

RGB and HSI of Image color space