Automated optical inspection system for digital TV sets

This article proposes a real-time test and verification system for full-reference automatic image quality assessment and verification of digital TV sets. Digital camera is used for acquisition of the TV screen content in order to ensure quality assessment of the content as perceived by the user. Test has been executed in three steps: image acquisition by camera, TV screen content extraction and full-reference image quality assessment. The TV screen content is extracted from the captured image in two steps: detection of the TV screen edge and transformation of the TV screen content to dimensions of the reference image. Three image comparison methods are incorporated to perform full-reference image quality assessment. Reference image for quality assessment is obtained either by grabbing the image from TV set or by capturing the TV screen content on the golden sample. Digital camera was later replaced with DSP-based camera for image acquisition and algorithm execution which brought significant performance improvements. The comparison methods were tested under constant and variable illumination conditions. The proposed system is used to automate the verification step on the final production line of digital TV sets. The time required for verification step decreased by a factor of 5 when using the proposed system on the final production line instead of a manual one.