Design and Calibration of a Dual-band Imaging System

Authors: Kise, Michio; Park, Bosoon; Lawrence, Kurt; Windham, William

Submitted to: Sensing and Instrumentation for Food Quality and Safety
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/12/2007
Publication Date: 11/6/2007
Citation: Kise, M., Park, B., Lawrence, K.C., Windham, W.R. 2007. Design and Calibration of a Dual-band Imaging System. Sensing and Instrumentation for Food Quality and Safety. 1(3): 113-121.

Interpretive Summary: Food safety in the poultry industry is ongoing problem. Several deaths occur each year from public consumption of contaminated poultry and/or meat. Potential contamination can occur when feces or ingesta is deposited on the surface of the carcass. Identification and separation of the birds contaminated by feces is very important to protect the consumer from a potential source of food poisoning. The current method of inspecting fecal contamination is through human visual observation with the criteria of color, consistency, and composition used for identification. Therefore, there is a need to develop science-based instrumentation which can reduce inspector fatigue, variability, insure continuous inspection, and provide a safe poultry food supply for the consumer. The objective of this research is to design and fabricate a compact, cost effective multispectral instrument and to collect and analyze spectra for real-time contaminant detection for poultry processing plants. The prototype system is developed and tested in the real environment and shows that it can effectively detect feces and ingesta on the surface of poultry carcasses.

Technical Abstract: The objective of this research was to design and fabricate a compact, cost effective multispectral instrument and to collect and analyze spectra for real-time contaminant detection for poultry processing plants. The prototype system developed in this research consisted of a multispectral imaging system, illumination system and an industrial portable computer. The dual-band spectral imaging system developed in this study was a two-port imaging system that consisted of two identical monochrome cameras, optical system and two narrow bandpass filters whose center of the wavelength are 520 and 560 nm with 10 nm FWHM, respectively. A spectral reflectance from a chicken carcass was collected and split in two directions by an optical system including a beamsplitter and lenses, and then two identical collimated lights were filtered by the narrow bandpass filters and delivered to the cameras. Lens distortions and geometric misalignment of the two cameras were mathematically corrected. The prototype system was tested at the real-time processing line and the preliminary results showed that the dual-band spectral imaging system could effectively detect feces and ingesta on the surface of poultry carcass. To improve false-positives without decreasing detection accuracy on actual contaminants, new thresholding algorithm with a polynomial function was developed and could eliminate more than 90% of the false-positive errors compare to the constant single threshold algorithm.