HSI color space

Color in the HSI color space is represented as three components hue, saturation, and intensity (Gonzalez and Woods 1992 Jain et al. 1995 Smith 1978). Any point in the RGB color space can also be specified using the HSI color model. The attribute hue defines the color of the point. Saturation specifies the amount of white added to the pure color. Finally, intensity specifies the brightness of the point. It is not clear if the HSI components are defined for linear RGB or nonlinear RGB space (Poynton 1997, 1998). Therefore, it is not possible to determine whether the components of the HSI color space refer to a physical 

Let c = [R, G, B] be a color in RGB space. The transformation from RGB space to HSI space is given by (Gonzalez and Woods 1992) 

Note that care must be taken not to perform the transformation for HSI values that would specify RGB values outside of the unit cube. Suppose we start with a red color [R, G, B] = [1, 0, 0]. If we transform this color to HSI space, we obtain [H, S, /] = [0, 1, ]. This is a maximally saturated color of intensity I = It is not possible to further increase the intensity to 1 while maintaining the same saturation. 

A generalization of the HSI color space, where the white point may be located at an arbitrary position on the triangle, is given by Smith (1978). This color space is known as the HSL color space. 

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The threshold selection method consists of two steps. The proposed selection method will utilize saturation formula base on HSI color space. Then, the resultant image will be used as the input for clustering algorithm. The steps are ... 

Thermochromic Liquid Crystals for Particle Image Thermometry, Fig. 4 Scatter plots of detected particles color data for (a) RGB, (b) HSI, and (c) POD color spaces... 

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