Design and calibration of a dual-band imaging system

Abstract

A prototype portable multispectral imaging system, in terms of design, fabrication, compactness, and cost effectiveness was developed for real-time contaminant detection in poultry processing plants. The prototype system developed in this research was a dual-band spectral imaging system that acquired two different spectral images simultaneously. This was accomplished by using a two-port imaging system that consisted of two identical monochrome cameras, optical components, and two interchangeable optical filters. Spectral reflectance from an object was collimated by lenses and split identically in two directions by a beamsplitter. Focusing lenses behind a beamsplitter projected each image on its respective sensor. Two optical bandpass filters determined the spectral characteristics of each image and are easily interchangeable. In order to co-register two-band images, a system-specific calibration algorithm was developed that corrected lens distortions and lens-sensor geometric misalignments. The prototype imaging system and the system calibration algorithm were tested for image registration accuracy. The imaging system acquired two-band images of 3D object with less than 8.1 μm error in terms of the position of the sensor. The prototype system was able to effectively detect feces (duodenum, cecum, colon) and ingesta on the surface of poultry carcasses.