Patent ID: 6470149
Filing Date: 2002-10-22
Classification: G02B

Abstract:
A distance measuring apparatus comprising:a light receiving device comprising at least one array of photoelectric conversion elements, wherein each of said photoelectric conversion elements converts light received thereon into an electric charge and accumulates the electric charge so that the accumulated electric charge is output in order from each photoelectric conversion element as an electrical picture signal; an A/D converter which converts the picture signal into digital image data; a converting device which performs a logarithmic transformation on the digital image data to replace the digital image data with sensor data; an operation device which performs a distance measuring calculation in accordance with the sensor data; a determining device which determines whether the calculated distance is effective, whether a contrast in a portion of the sensor data is equal to or higher than a predetermined contrast value and whether an object brightness is equal to or greater than a predetermined object brightness value, in accordance with the sensor data; and a prohibiting device which prohibits said converting device from performing the logarithmic transformation on the digital image data when said determining device determines that the calculated distance value is not effective, that the contrast in the portion of the sensor data is lower than the predetermined contrast value and that the object brightness is equal to or greater than the predetermined object brightness value; wherein, when said converting device is prohibited from performing the logarithmic transformation on the digital image data, a second picture signal output from said light receiving device is converted into second digital image data and, without the logarithmic transformation being performed on the second digital image data, the distance measuring calculation is performed in accordance with the second picture signal.