Modified pressure system for imaging egg cracks.
One aspect of grading table eggs is shell checks or cracks. Currently, USDA voluntary regulations require that humans grade a representative sample of all eggs processed. However, as processing plants and packing facilities continue to increase their volume and throughput, human graders are having difficulty matching the pace of the machines. Additionally, some plants also have a problem with micro-cracks that the graders often miss because they are very small and hard to see immediately post-processing but grow and become readily apparent before they reach market. An imaging system was developed to help the grader detect these small micro-cracks. The imaging system utilized one image captured at atmospheric pressure and a second at a slight negative pressure to enhance the crack and make detection much easier. A simple image processing algorithm was then applied to the ratio of these two images, and the resulting image, containing both cracked and/or intact eggs were color-coded to simplify identification. The imaging system was capable of imaging 15 eggs in about 0.75 s, and the algorithm processing took about another 10 s. These times could easily be reduced with a compiled program specifically written for the application. In analyzing 1000 eggs, the system was 99.6% accurate overall with only 0.3% false positives, compared to 94.2% accurate overall for the human graders with 1.2% false positives. An international patent on the system has been filed, and further automation of the system is needed.