1989 Volume 51 Issue 6 Pages 29-36
Comparison of the visual range on the rear of tractor by images through 3 types of conventional rearview mirrors, and through 3 sets of two plane/convex mirrors which were cited as twe-mirror method in the previous report, is presented.
For the evaluation of visual perception, pattern boards were spread out on the ground behind tractor, and vertical pattern plates were stood at each point on the pattern boards. Detailed sizes of distorted mirror images of horizontal or vertical patterns were measured.
The two-mirror method was advantageous to watching rearward area rather near by the tractor, though with a slight shorting of image in the longitudinal direction. In the case of rearview mirrors, the indirect visual range covered the area from the side of tractor rear wheels to the central part of tractor rearward, but the area around the lower hitch points remained as a dead angle of view. The mirrors gave images lengthened in the vertical direction.
