Mining the Differences between Penninc and Vostaert

A convergence adjustment device for color video-projectors having three monochrome tubes, each projecting an image of a give color on a screen. This device acts on the scanning of the second and third tubes for superimposing, on the screen, their images on that of the first tube. This device is of the digital type. It comprises a RAM in which correction values are stored corresponding to correction of the scanning currents for the different zones into which the image is divided. These values are restored in synchronism with the scanning of the zones during normal operation. The device also comprises a microprocessor for modifying, during the adjustment phase, the stored values as a function of the ordes issued by the user who makes this adjustment by observing the image. The user's actions in a manual mode affect only a single one of the zones. In an automatic mode, adjustments are effective on groups of zones.