Patent ID: 8781780

Claim:
An electro-optical distance measuring method for projecting a light from a light source toward an object to be measured, for receiving a reflection light from the object to be measured at a photodetection unit, for receiving the light from said light source as an inner light via an inner optical path by said photodetection unit, and for measuring a distance to the object to be measured according to the result of photodetection of said reflection light and said inner light of said photodetection unit, wherein said method comprises a correction information acquiring step where a reference light quantity is set with respect to a light quantity of said inner light, and the change in photodetection signal is detected from said photodetection unit when said light quantity of said inner light is changed, and the relation between light quantity change and phase change is acquired as correction information, and a calculating step, wherein said calculating step is to obtain the deviation of phase from said correction information based on the difference in the light quantity between the light quantity of said reflection light and said reference light quantity, said deviation is set as a correction value and to calculate a distance from said correction value and the result of photodetection of said reflection light and said inner light of said photodetection unit.