Application of Multispectral Imaging for Identification of Systemically Diseased Chicken

A multispectral imaging system for automated inspection of wholesome and systemically diseased chickens was developed and demonstrated. The disease of septicemia was selected as the detection target because it is the most common chicken disease in US. From visible/near-infrared reflectance spectra of poultry carcasses, average CIELAB L*(lightness), a*(redness), and b*(yellowness) values were analyzed. The difference of lightness between wholesome and septicemic chickens was significant. The multispectral imaging system consisted of a backilluminated CCD camera and a spectrometer with four narrow-band interference filters for 488, 540, 580, and 610 nm wavelengths, respectively. The 16-bit multispectral images of chicken carcasses were collected for image processing and analysis. Image processing algorithms, including image registration, flat-field correction, image segmentation, region of interest identification, feature measurement, and symptom recognition, were developed to differentiate septicemic chickens from wholesome ones. The image from 610-nm wavelength was used to create a mask to extract chicken images from background. The average reflectance intensities at 488, 540, 580, and 610 nm from different parts of the carcass in the front side were calculated. Moreover, four normalization methods and four normalized differentiation methods between two wavelengths were also calculated for comparison. Decision tree was applied to generate thresholds for differentiation between wholesome and septicemic chickens. Images were collected at three time frames. The images from the first time frame were used to generate first thresholds that were tested by the images from the second time frames. Then, the images from the first and second time frames were used together to generate second thresholds. The first and second thresholds were tested by the images from the third time frame, respectively. The results showed that using average intensity at 580 nm from the region of interest, 98.6% of septicemic chickens and 96.3% of wholesome chickens could be differentiated from each other. More training data could help to generate more appropriate thresholds used at different time frames.