For more explanation of this table and others like it, see Words You Need to Know in the Preface. A filter whose properties vary across an image depending on the local characteristics of the image pixels. Contour A path in an image along which the image intensity values are equal to a constant. Edge A curve that follows a path of rapid change in image intensity. Edges are often associated with the boundaries of objects in a scene.
Edge detection is used to identify the edges in an image.
A quantitative measurement of an image or image region. Examples of image region properties include centroid, bounding box, and area. Histogram A graph used in image analysis that shows the distribution of intensities in an image. The information in a histogram can be used to choose an appropriate enhancement operation. For example, if an image histogram shows that the range of intensity values is small, you can use an intensity adjustment function to spread the values across a wider range.