Chapter 4. Image Histograms

We started off with simple grayscale transformations and gradually moved to image filtering, thresholding, and morphological operations. At the most fundamental level, there is something in common among all the image-processing and computer vision algorithms that we have discussed in this book so far. In each of these processes, there was always some form of computation that was being performed at every pixel. The result of the computation at the input stage dictated the output value of a pixel in the output image (we usually termed it the corresponding output pixel). What this essentially meant was that the output of all of these operations was images of the same size (dimensions) as the input image, and there was one-to-one correspondence between the pixel locations in the input and the output images: this correspondence were governed by the nature of the computation that was performed. For example, when we talked about image averaging, we performed the average...