Fig. 3.

The pencil-like imaging spectrometer was utilized for ripeness testing and myoglobin detection. A white LED array lamp was used as the light source. (a) and (b) show the reflectance spectra from green and ripe bananas, respectively. The green banana exhibited a sharp downward trend at the red light band. (c) and (d) show the reflectance spectra from the muscle and fat parts of pork, respectively. The insets in (c) and (d) illustrate the reflectance around 540 nm range. There is an absorption around 540 nm in (c) due to the myoglobin in the muscle part of pork.