From the Filter menu, select Extract. This tutorial on image editing software covers the use of the extraction filter in Photoshop. In Photoshop CS3 there are many ways to remove an image from the background, and the extraction filter is one of them. Learn the advantages and disadvantages of using the extraction filter in Photoshop in this video tutorial.
But there is too much time difference %26 quality in extraction% 26 Refine Edges, Extract is the best complement for still photo editors. 2D convolution works on two images, one works as an input image and the other, called the core, serves as a filter. The mathematics of many filters can be expressed primarily using 2D convolution, such as smoothing and focusing images and detecting edges. The moving average filter replaces each pixel with the average pixel value thereof and a neighborhood window of adjacent pixels.
While a convolution is a filtering operation, correlation measures the similarity of two signals, comparing them as they move relative to each other.
