Real-Time Optical Hough Transform for Industrial Inspection

We describe a real-time optical Hough transform (HT) inspection system and show quantitative inspection results using an industrial inspection application. The HT architecture uses an electronically addressed liquid crystal television (LCTV) as the real-time spatial light modulator, a novel selective edge-enhancement filtering technique, and realizes multiple slices of the HT with a computer generated hologram. The industrial case study of the inspection of cigarette packages is used to benchmark the HT processor. A test set of 100 packages is presented to the processor to qualify its effectiveness. The statistical significance of these finite test set results is also examined.