Optical distance measurement apparatus provided with smear detector device
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorMasahira Akasu
Life of this patent
Estimating the term…
Abstract
An optical distance measurement apparatus for measuring the distance to an object 7 on the basis of the round-trip time of the light to and from the object. 7 includes an object detector means 32 and a smear detector means 33. The smear detector means 33 detects a smear when the ratio of unsuccessful measurements (i.e., the measurements by which no object is detected) is greater than or equal to a predetermined level. Alternatively, the number of successive measurements of a distance less than a predetermined threshold level (e.g., 50 meters) is stored in a counter, and the smear is detected when the content of the counter becomes greater than or equal to a predetermined number.
Claims6
An optical distance measurement apparatus comprising:
- light transmitter means for radiating light toward an object a distance to which is to be measured;
- light receiver means for receiving said light radiated from said light transmitter means and reflected by said object, said light receiver means generating a signal corresponding to a received light;
- distance measurement means, coupled to said light transmitter means and said light receiver means, for determining a distance to said object periodically on the basis of a round-trip time of said light travelling forward from said light transmitter means to said object and backward from said object to said light receiver means;
- object detector means, coupled to said light receiver means, for determining whether or not an object is detected on the basis of a level of said signal output from said light receiver means;
- and
- smear detector means, coupled to said object detector means, for calculating a ratio of a number of measurements by which said object is not detected to a total number of measurements made periodically by said distance measurement means over a predetermined length of time, wherein said smear detector means detects a smear when said ratio is greater than or equal to a predetermined level.
An optical distance measurement apparatus comprising:
- light transmitter means for radiating light toward an object a distance to which is to be measured;
- light receiver means for receiving said light radiated from said light transmitter means and reflected by said object, said light receiver means generating a signal corresponding to a received light;
- distance measurement means, coupled to said light transmitter means and said light receiver means, for determining a distance to said object periodically on the basis of a round-trip time of said light travelling forward from said light transmitter means to said object and backward from said object to said light receiver means;
- counter means, coupled to said distance measurement means, for storing a number of successive measurements of a distance less than a predetermined threshold level, said measurements being performed by said distance measurement means;
- and
- smear detector means, coupled to said counter means, for detecting a smear when a content of said counter means becomes greater than or equal to a predetermined number.
Dependencies are inferred from the claim text.