This chapter was dedicated to the presentation of color image processing techniques that build upon the grayscale methods of previous chapters. The meaning of color was explained, accompanied by an introduction to color image manipulation. Then, color image thresholding in various color channels was visited with examples, denoting the significant of a proper color channel. Several techniques for color image illumination enhancement were also presented and compared to their grayscale versions. Finally, two alternative ways for red eye reduction in photographs were developed and explained. More specifically, this chapter covered:
imrotate
, imresize
, and flipdim
im2bw
In the next chapter, we will present various image filtering techniques, that can be used either for repairing flawed images or to achieve artistic results. Spatial and frequency filters will be explained, using practical examples, to understand their importance. Several usual image processing problems will be addressed using combinations of filtering methods and other techniques that you have learned so far in this book.