Based on the PSD analyses, it is found that the signal of PSD is nonlinear when there exist backgroundlight.
根据光电位置敏感器件的原理及特征方程，分析了存在背景光时它的输出信号是非线性的。
2
The light at the background should be 1 stop brighter than the main, but the backgroundlight should drop off by a stop when it hits the models back.
而背景光应该比主光强1档，如果当背后的光强于主光是，应当让模特远离背景。
3
The backgroundlight influences phototaxis of round scad on the horizontal gradient condition, the influence weakens with the increasing light intensity.