An image analysis approach to identification and measurement of marbling in the intact pork loin

An image analysis method for identifying marbling on exposed boneless pork loin surfaces was developed, solving the problem of influences from uneven lean colour. Comparing results from RAW and JPEG images of the mid-loin pork chop showed that, except at very high marbling levels, estimation of %IMF (intramuscular fat) was similar with both image types (R² = 0.72 and 0.74 respectively). Marbling calculated from JPEGs was positively related to %IMF, but also diverged as %IMF increased. Estimations of %IMF at the mid-loin chop from JPEGs of external loin sites showed marbling on the posterior face to be the most strongly related (r = 0.72, P < 0.0001), followed by the ventral surface (r = 0.62-0.64, P < 0.0001), and the anterior face (r = 0.56, P < 0.0001). For on-line application, computing speed is important. This study suggested that an image capture system could be reduced to the capture of a cyan-filtered monochrome JPEG image for analysis.