Patent ID: 8718962

Claim:
A distance-measuring device, comprising: a lighting component, emitting a detecting light to a measured object to generate a reflective light; a first lens, disposed in a transmission path of the reflective light; an image sensor, the reflective light being focused by the first lens onto the image sensor for the measured object to form an image at a first imaging location, a distance-calculating circuit calculating a measured distance between the distance-measuring device and the measured object according to the first imaging location, a focal length of the first lens, and a first predetermined distance between the lighting component and the image sensor; a temperature sensor for measuring the ambient temperature of the distance-measuring device; a temperature compensation calculating circuit for calculating a first calibrated imaging location according to the ambient temperature and the first imaging location, and providing the first calibrated imaging location to the distance-calculating circuit for calibrating the measured distance; and a parameter-calculating circuit utilized for providing a first calibrating parameter and a second calibrating parameter to the distance-measuring circuit; the first calibrating parameter is utilized for calibrating a first sensing-error angle and a second sensing-error angle of the image sensor; the second calibrating parameter is utilized for calibrating a lighting-error angle rotated by the detecting light emitted by the lighting component; wherein the distance-calculating circuit calculates the calibrated measured distance according to the following formula: D M =1 /[A×D CS — CAB +B]; wherein D M represents the calibrated measured distance; A and B respectively represent the first calibrating parameter and the second calibrating parameter; and D CS — CAB represents the first calibrated imaging location; wherein a relationship among the first calibrating parameter, the first sensing-error angle, and the second sensing-error angle is represented by the following formula: A =(cos θ CS2 ×cos θ CS1 )/( D F ×L ); wherein θ CS1 represents the first sensing-error angle θ CS2 represents the second sensing-error angle; and L represents the first predetermined distance between the lighting component and the image sensor; wherein a relationship between the second calibrating parameter and the lighting-error angle is represented by the following formula: B =tan θ LD /L; wherein θ LD represents the lighting-error angle.