Patent US 4,189,744

The disclosure is directed to an apparatus for generating video-representative signals which represent one or more operator-selected portions of an existing scene. In accordance with the invention, frame storage means are provided for storing an array of elemental pixel values representative of the video content of the individual elemental areas of the scene. As defined herein, video content is intended to include shading and/or coloration of monochrome or color images. Means are provided for interrogating the frame storage means and for tabulating the pixel values stored in the frame storage means. Operator controllable means are provided for selecting one or more of the pixel values of the tabulation. Means responsive to the selected values are provided for forming video-representative signals corresponding to those portions of the scene having the selected pixel values. In the preferred embodiment of the invention there are provided means for displaying the tabulation of the pixel values. In this embodiment, the means for forming video-representative signals comprises means for detecting the boundaries of those portions of the scene having the selected pixel values and for storing outline-representative transition points as a function of the detected boundaries. Accordingly, an operator can select desired portions of an existing scene and automatically obtain stored contour outlines of those portions.