以阶跃型反射率分布为例，分析了像素尺寸对相位测量轮廓术(PMP)测量精度的影响情况。仿真结果表明相位测量误差大小随感光单元覆盖的相位范围增加而增加，即采用高分辨率探测器可以得到高的测量精度；相位测量误差大小与阶跃在感光单元上的位置有关，存在导致最大误差的位置，并且该位置与阶跃相对幅值有关；相位测量误差大小随阶跃相对幅值增大而增大，偏向反射率高的方向。研究结果为PMP测量系统设计中图像探测器选择、测量精度评价提供了依据。

The measurement error of phase measurement profilometry caused by pixel size of detector under step distribution of reflection rate is studied through theoretical analysis and simulation. The results are gained as follows. First, measurement error of phase is increased as the phase range covered by pixel increases. It means that higher measurement accuracy could be obtained if detector with higher resolution is used. Second, the error is related to the position of step on photosensor unit. It exists that a position causes maximum error. And the position is related to relative amplitude of step. Third, the error is increased as relative amplitude of step increases. And the error leans to direction of high reflection rate. The research shows the basis for the image detector choice and the measurement accuracy evaluation in the design of PMP measurement system.