Abstract: A video image is extracted and stored as a geometric figure by generating a binary pixel map of the image. The binary pixel map contains one bit for each pixel in the image, representative of the value of a characteristic feature of that pixel relative to a threshold range. A crack following algorithm locates the border of a group of contiguous pixels all having the same binary value. This border defines the boundaries of the scanned image. It is smoothed by a recursive adaption technique to generate one or more polygons related to the shape of the image.

Abstract: To produce a simulated airbrush spray pattern comprising a random pattern of pixels in a video image, multiple source arrays defining random variations of one or more video image parameters are created. Each time that an airbrush spray pattern is to be generated on a video display, the source arrays are individually retrieved and used to control the characteristics of corresponding pixels in the video image. The arrays are varied on a regular basis to create a random pattern in the image that simulates the effects of an airbrush spray. Various modifications can be used to create particular effects and position dependent textures, such as the short, random streaks that are produced by chalk.