Defect Detection Based on Edge Detection and Connected Region Filtering Algorithm

In the production process of the print heads, due to the performance of the device and other external factors, some dead pixels affecting the quality of the print heads are formed on the surfaces of them. With the development of image processing technology, it is a good choice to use the related method of image processing to detect dead pixels. Aiming at the problem of accurately detecting the dead pixels of the print head, this paper proposes an identification method using the edge detection algorithm and the connected region filtering algorithm based on linear fitting. Firstly, this paper uses the Retinex algorithm to enhance the original image, and then, minimum filtering and wiener filtering are adopted in order to make further enhancement and remove noise. Secondly, edge detection algorithm is adopted to detect the textures of interference areas and dead pixels when identifying them. Additionally, this paper proposes the algorithm of screening connected regions based on linear fitting to eliminate all interference areas. Finally, the author reserves the dead pixels that need to be identified and then positions them. The experimental results show that this method can accurately detect the dead pixels in the line CCD scanned image and can be applied to at least five types of print head surface dead pixels.