| 摘要 |
PURPOSE:To make it possible to detect the defective part in external appearance in the specified direction when this method is applied on the visual inspection of a product by comparing the characteristics on a reference image and an image to be compared by using a prediction operating expression indicating the associated degree between image data. CONSTITUTION:Reading scanning of a line sensor 10 is performed for a product in conveyance by (m) times. In a prediction filter 30, the prediction operation for the image data for every line which are obtained at the (m + 1)th time is performed. The difference between the prediction data at the (m + 1)th time and the actually obtained image data is computed. The result of the computation is outputted into a comparator 40 as a prediction error epsilon. In the comparator 40, the prediction error epsilon for every time is compared with a threshold value. When the prediction error is larger than the threshold value, the warning signal which indicates that there is the abnormal part in the image data that are obtained by the reading scanning from the first time to the (m + 1)th time is outputted. Even if the abnormal parts continue in the specified direction, the presence of the abnormal parts can be positively detected. |
