Real time color purity and convergence measurement algorithms for automatic ITC adjustment system

Abstract

In manufacturing CPT (Color Picture Tubes) used in TV sets and monitors, an ITC (Integrated Tube Components) adjustment process is involved. Automating the ITC adjustment process needs fast and robust visual sensing/measurement. Real time color purity and convergence measurement algorithms are described. Existing color purity measurement algorithms for ITC adjustment system often take too much time to detect color purity. Moreover, for convergence measurement, measurable data is not sufficient for accurate detection. To overcome these difficulties, real time vision system with 9 area cameras and many linear array cameras is developed. Area cameras are used for color purity measurements and linear array cameras are used for convergence measurements. To devise the purity measurement algorithm, the characteristics of CPT microscopic images are analyzed. To measure the exact color purity, several methods are selectively applied for calculating color purity depending on the conditions of CPT screen. For convergence measurement, special test CPT with no shadow mask and no black matrix is manufactured and a new measurement algorithm is developed using fuzzy inference and a priori knowledge taken from the specially manufactured CPT. The proposed algorithms are successfully applied as described in the experimental results.<>