The Purpose of Image Histogram Analysis

Image histogram analysis is very useful in image processing, some of the purposes are:

1. Selecting appropriate digitizing parameter. Histogram can be used to visually judge if an image is in an appropriate range of gray level. Ideally, digital image should use all available gray scale range, from minimum to maximum. This is important to optimize the display and other imaging devices to use all their potential capability. The imaging devices will be optimum if the they display (or print) the image data that contain optimum usage of its format (for example 0-255 for 8bit monochrome image).
2. Selection of Thresholding Level. One of image processing technique is thresholding, where all pixels above certain brightness level is maximized to the maximum value and others are minimized to the minimum value. This is very useful in object and background separation if there is significant difference between an object and its background on an image.