Hue, Saturation, and Intensity are represented as HSI in HSI colour model. The HSI model is used as an alternative to, or alongside the RGB representation. In this model, the hue of a colour is its angle measure on a colour wheel. Pure red have hue value as 0°, pure green have hue value as 120°, and pure blues have hue value as 240°. Neutral colours like white, grey, and black are set to hue value 0° for feasibility. Intensity is total brightness of the colour and also defined numerically as the average of the equivalent RGB values. Saturation is a measure of a colour’s purity/greyness. Purer colours have a saturation value closer to 1, while greyer colours have a saturation value closer to 0. Video signals and image signals are recorded
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The three colours are spread evenly on the circle over 360. Red is assigned to an angle of 0, while green to an angle of 120, blue to an angle of 240 and remaining colours can be found on the other points. Grey scale is located in the centre of the hue circle because all shades of grey are an even combination of the three main colours.
The saturation of a colour is the purity of a colour and tells the amount of white contained in the pure spectral colour. To represent the two hue and saturation, a vector pointing to the pure spectral colour is used and the value of this vector gives the saturation. For an example, an input signal of R=B and G=0 is given and this results in a pointer to 315 (Magenta). Because the magnitude of G is zero, there is no white contained in the representation of magenta and therefore the length of the vector is one. The intensity perception of a colour is represented in the HSI model by a second pointer and it is located at right angle to the hue–saturation vector because all colours fade either into pure white or black when the intensity is increased, or …show more content…
As the RGB to HSI image processing algorithm is be implemented in hardware, a digitised version of the three primary colours are used. For the implementation of the RGB to HSI algorithm in hardware R, G, B are used specifically to indicate digitised inputs of red, green and blue. Quantisation of each input signal is eight bits which results in a 24 bit RGB images, these are standard for high quality image reproduction and can be used in image recording formats such as BMP, PPM and Sun Raster
The three colours are spread evenly on the circle over 360. Red is assigned to an angle of 0, while green to an angle of 120, blue to an angle of 240 and remaining colours can be found on the other points. Grey scale is located in the centre of the hue circle because all shades of grey are an even combination of the three main colours.
The saturation of a colour is the purity of a colour and tells the amount of white contained in the pure spectral colour. To represent the two hue and saturation, a vector pointing to the pure spectral colour is used and the value of this vector gives the saturation. For an example, an input signal of R=B and G=0 is given and this results in a pointer to 315 (Magenta). Because the magnitude of G is zero, there is no white contained in the representation of magenta and therefore the length of the vector is one. The intensity perception of a colour is represented in the HSI model by a second pointer and it is located at right angle to the hue–saturation vector because all colours fade either into pure white or black when the intensity is increased, or …show more content…
As the RGB to HSI image processing algorithm is be implemented in hardware, a digitised version of the three primary colours are used. For the implementation of the RGB to HSI algorithm in hardware R, G, B are used specifically to indicate digitised inputs of red, green and blue. Quantisation of each input signal is eight bits which results in a 24 bit RGB images, these are standard for high quality image reproduction and can be used in image recording formats such as BMP, PPM and Sun Raster