An image is composed of pixels of different values (colors). The distribution of pixel values across the image constitutes an important characteristic of this image. This chapter introduces the concept of image histograms. You will learn how to compute a histogram and how to use it to modify the image's appearance. Histograms can also be used to characterize the image's content and detect specific objects or textures in an image. Some of these techniques will be presented in this chapter.
In this chapter, we will cover the following recipes:
- Computing the image histogram
- Applying lookup tables to modify the image's appearance
- Equalizing the image histogram
- Backprojecting a histogram to detect the specific image content
- Using the mean shift algorithm to find an object
- Retrieving similar images using histogram comparison
- Counting...