A digital leaf-area measuring system using a television scanned conveyor
Authors: Buckley, D.J., Reid, W.S. And H.D. Voldeng
Description: The measurement of leaf area is important in plant breeding, growth, and competition studies and in determining insect and virus damage to plants. Because large numbers of samples are usually considered, a rapid, accurate method of measurement is required and digital outputs suitable for automatic computer-compatible data recording equipment are desirable. The many analog photoelectric leaf area planimeters previously described (2, 3, 4, 6, 7, 8) are not readily adaptable to sample feed mechanisms for rapid sample measurement require elaborate optical systems to reduce errors due to variation in trans mission, reflectance, and texture characteristics of different leaves (5) require frequent calibration to compensate for aging of light sources and photocells and lack digital outputs necessary for automatic data recording. Digital leaf area planimeters with conveyor transports for rapid sample measurement are available commercially (Paton Industries Pty. Ltd., 35 Henry St., Stepney, Australia, and Hayashi Denko Co. Ltd., Tokyo, Japan). The former instrument uses discrete photocells in a digital array and the latter uses a scanning light spot with digital processing to overcome errors due to variation in leaf light transmission or reflectance. However, these instruments can only accommodate leaves up to 10 cm in width and do not provide digital outputs for data recording. The instrument described here can measure the area, the maximum length, and the maximum width of leaves up to 18.5 cm in width and 99,999 cm2 in area, and uses a leaf-flattening conveyor for rapid measurement of samples. The instrument, an adaptation specifically for leaf area measurement of a previous device (1), uses a standard close-circuit television camera to provide transverse scan measurement and a conveyor to provide longitudinal scan measurement. The measurements are displayed on three separate digital readouts and binary-coded decimal (BCD) outputs are provided for data recording.
Keywords: a digital leaf-area measuring system using a television scanned conveyor
Citation: Buckley, D.J., Reid, W.S. and H.D. Voldeng 1973. A DIGITAL LEAF-AREA MEASURING SYSTEM USING A TELEVISION SCANNED CONVEYOR. Canadian Agricultural Engineering 15(2):107-109.
Start page number: 107
End page number: 109