Agriculture Reference
In-Depth Information
(a)
(b)
(c)
(d)
(e)
(f)
(g)
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FIGURE 14.7
Various fruit images: (a) PL filtering monochrome image; (b) non-PL fil-
tering image; (c) glossing eggplant; (d) partially dull eggplant; (e) rotten fruit monochrome
image; (f) rotten fruit fluorescence image (UV excitation); (g) rind puffing fruit; (h) normal
fruit; (i) x-ray image of fruit in (g); and (j) x-ray image of fruit in (h).
(Slaughter et al., 2008; Kondo et al., 2008), because the injured parts have slightly
different colors. Figure 14.7(e) and (f) shows the monochrome and fluorescent images
of a rotten orange fruit. Kurita et al. (2009) constructed a new machine vision using
white and UV LEDs to obtain color and fluorescent images by one camera.
X-ray is a radiation and a kind of electromagnetic wave with a wavelength in the
range of 10 to 0.01 nm, corresponding to frequencies in the range 30 PHz to 30 EHz.
They are shorter than ultraviolet rays but longer than gamma rays. An x-ray is one of
the effective methods to inspect the internal structures of agricultural products due
to the ability of transmittance. The intensity of energy exiting the product depends
on the incident energy, absorption coefficient, and density of the sample thickness.
Because of the high moisture content in fruits and vegetables, water dominates x-ray
absorption. X-ray is usually classified into two: soft x-ray (x-ray tube voltage: about
0.12 to 12 keV; 10 to 0.10 nm wavelength) and hard x-ray (about 12 to 120 keV; 0.10
to 0.01 nm wavelength) because of their penetrating abilities.
This transmittance image can apply to many agricultural products such as hol-
low heart in potato (Nylund and Lutz, 1950), split pits in peaches (Han et al., 1992),
