We have built a database containing 206 images of the 16
varieties considered from Chinese five locations. To
acquire the images we used a 2/3 in. CCD digital camera
(Kodak DX 7590) with a white background. Illumination
was provided by a 22 W light source (TCL YH, 6500K,
Ra>80, EX-D: 3 band Daylight).
Images were taken with a 2048 × 1536 pixel resolution on
a white background, which can be easily subtracted by
common segmentation method. Each image concluded
100 grains. The distance of the lens and sample was fixed
with 12.5 cm.
As a cheap instrument for image acquisition, a CCD
camera was often used by machine vision systems forcrop quality evaluation, and the images acquired were
commonly in three-dimensional RGB colour space.