An apparatus and method for stacked sheet counting with camera array

There is an emerging requirement for quality control like sheet-counting in printing and packaging industry, where machine vision methods are widely adopted due to their nondestructive and real-time merits. However, the conventional single-camera scanning systems often suffer from insufficient resolution while handling the sheet-counting issue of ultrahigh stacks. To solve the problem, we present a new apparatus using camera array and advanced image processing algorithms. In this paper, the system architecture of the apparatus is briefly described. Much emphasis is exerted on the line detection of images based on an improved Canny edge algorithm. Particularly, the fusion of results from multi-camera imaging is described in details. Through more than one year's test in factory production lines, it is demonstrated that our apparatus can satisfy the high-accuracy requirement of real-time sheet-counting task with an error less than 6%.