Color processing examples

Example 0:

• Linear Stretch of intensity:

  

• Enhance/reduce saturation:

  

Example 1:

• Linear stretch:

  Original image and its histogram:

  

  

  Histogram of intensity before and after processing:

  

  Processed image and its histogram:

  

  

• Histogram equalization

  Histogram of intensity before and after processing:

  

  Processed image and its histogram:

  

  

• Increment of saturation

  Histogram of intensity before and after processing:

  

  Processed image and its histogram:

  

  

Example 2:

Histogram of intensity before and after linear stretch and saturation inhancement:

Processed image and its histogram:

Example 3:

A color image can be either smoothed or sharpened by the regular smoothing and sharpening methods discussed for gray-scale images applied to each of the R, G, and B components. As these three color components may be modified differently, the color attribute (hue and saturation) of each pixel may be different from the original.

Alternatively, the smoothing/sharpening methods can also be applied only to the intensity component after RGB-HSI conversion, so that the color attributes of the image (hue and saturation) remain the same.

An example is shown below, the original image (left) is smoothed (middle) and also sharpened (right) by typical Gaussian and Laplacian convolution kernels.