03-05-2014, 02:48 PM
Pseudo / Color Image Processing
Color Image Processing
Two major areas of Color Image Processing
Pseudo Color Image Processing
Assigning colors to gray values based on a specified criterion
Full Color Image Processing
Processing Image in color
Further two categories
Process each component individually and then form a composite processed color image from the components.
Work with color pixels directly. In RGB system, each color point can be interpreted as a vector.
c(x, y)=[cR(x, y), cG(x, y), cB(x, y)]
Intensity Slicing
Using a plane at f(x, y)=li to slice the image function into two levels.
If an image is interpreted as a 3-D function, the method can be viewed as one of placing planes parallel to the coordinate plane of the image
Each plane “slices “ the function in the area of intersection
Two color images whose relative appearance can be controlled by moving the slicing plane up and down the gray-level axis
Gray-level to color assignments are made according to the relation : f(x,y)= ck if f(x,y) Vk (P planes, P+1 intervals)
Plane is useful for geometric interpretation of the intensity slicing technique
Gray Level to Color Transformation
Achieve a wide range of pseudo color enhancement
Perform three independent transformations on the gray levels of any input pixels; these results are fed separately into the red, green, and blue channels of a color television monitor. (Fig. 6.23)
Can be based on smooth, nonlinear functions, which, as might be expected (based on a single monochrome image)
Piecewise linear function (Fig. 6.19)
Obtain various degrees of enhancement (Fig.6.24)
Changing the phase and frequency of each sinusoid can emphasize ranges in the gray scale
Basics of Full Color Image Processing
Two categories:
Process each component individually and then form a composite processed image from the individually processed components
Work with color pixels directly
Color pixel are vectors
Let C be an arbitrary vector
Two conditions must be satisfied for pre-component and vector-based
Has to be applicable to both vectors and scalars
The operator must be independent of the other components