Patent US 3,978,324

In an automatic inventory system for crops, especially tree-borne crops, an airborne television camera views the area being surveyed and delivers an analogue video signal which is converted into a series binary digital signal by a level detector. The serial digital signal is received in a shift register that delivers a parallel digital output to a computer. The shift register is controlled by shift pulses derived from a pulse generator that has the video signal applied to it to maintain the pulses in synchronism with the camera operation. The computer receives the information from the shift register a frame at a time and determines from it parameters such as the average size, and spacing of crop-bearing trees and their numbers.