Patent ID: 9030676
Filing Date: 2015-05-12
Classification: G01B,G01S

Abstract:
1. A spatial information detection device comprising: a light projecting unit configured to emit signal light to a space including a predetermined intended area; a light receiving unit configured to receive light from the space; a modulation signal generation unit configured to generate a modulation signal and provide the modulation signal to the light projecting unit; a demodulation signal generation unit configured to generate a demodulation signal and provide the demodulation signal to the light receiving unit; a calculation unit configured to generate spatial information regarding the intended area; and a correction information provision unit, wherein: the modulation signal is defined as a square wave signal having high and low level periods appearing alternately, each of the high and low level periods having its length randomly selected from integral multiples of a predetermined unit time period; the light projecting unit is configured to, upon receiving the modulation signal, modulate light with the received modulation signal to generate the signal light; the demodulation signal is defined as a signal which has the same waveform as that of the modulation signal or that of a signal obtained by inversion of the modulation signal; the light receiving unit is configured to produce an amount of electric charges corresponding to an intensity of light received from the space within a collection time period defined by one of a first period in which the demodulation signal has a high level and a second period in which the demodulation signal has a low level, and accumulate the electric charges produced within the collection time period over a predetermined accumulation time period longer than the collection time period to generate signal electric charges; the correction information provision unit is configured to generate correction information regarding electric charges which the light receiving unit produces in response to light from an unintended area existing between the intended area and a set of the light projecting unit and the light receiving unit; and the calculation unit is configured to correct by use of the correction information the amount of the signal electric charges as an amount of intended electric charges corresponding to the electric charges which the light receiving unit produces in response to light from the intended area, and generate the spatial information based on the amount of the intended electric charges.