In the previous chapter, we covered signal processing techniques for one-dimensional, time-dependent signals. In this chapter, we will see signal processing techniques for images and sounds.

Generic signal processing techniques can be applied to images and sounds, but many image or audio processing tasks require specialized algorithms. For example, we will see algorithms for segmenting images, detecting points of interest in an image, or detecting faces. We will also hear the effect of linear filters on speech sounds.

scikit-image is one of the main image processing packages in Python. We will use it in most of the image processing recipes in this chapter. For more on scikit-image, refer to http://scikit-image.org.

We will also use OpenCV (http://opencv.org), a C++ computer vision library that has a Python wrapper. It implements algorithms for specialized image and video processing tasks, but it can be a bit difficult to use. An interesting (and simpler) alternative is SimpleCV...