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GREEN SEED COAT COLOUR RETENTION IN LENTIL - University ...

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perceive colour. Cone cells are used in brighter conditions and are responsible for<br />

perception of colour. People that are colour blind do not have fully functioning<br />

cone cells (Montgomery, 2007). The colour that is perceived by the cone cell of the<br />

eye is the wavelength that the object reflects (Lew, 2001).<br />

Every person sees different colours somewhat differently. Across a<br />

population of people the range of colour perception is very large from complete<br />

colour blindness to an ability to perceive colours in the two extremes of the visible<br />

light range. This variability makes the use of machines intriguing. If machines are<br />

calibrated properly and have the ability to consistently classify colour, the<br />

opportunity exists to have reliable and repeatable measurement of colour across<br />

many different environments. With machines it is possible to have repeatable<br />

measurements across machines, which is not possible between humans.<br />

Instruments can be used to accurately and consistently determine the colour<br />

of seed samples. The Acurum ® machine (Figure 2.1) is a computerized colour<br />

analyzing machine developed by DuPont. The computer used a Windows ® based<br />

personal computer operating at 3 gigahertz. Before each sample was analyzed the<br />

machine calibrated itself using an internal colour card. This was important because<br />

the machine operated in a dusty environment that could affect analysis. The colour<br />

card had proprietary colour definitions, not from any international standards. The<br />

machine uses a camera to record digital images of one side of individual seeds as a<br />

sample passes by in a single layer on a conveyor belt. The camera captures digital<br />

images at a size of 768 × 1024 pixels as white LED strobe lights flash. The images<br />

are analyzed in a bitmap format with an eight bit colour display. Neural networks<br />

8

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