Distance calculator and distance calculation method
View Patent ↗In order to be able to measure a distance with disparity resolution of a stereo camera or less and precisely measure a relative distance to a target even in the event of degradation of the imaging condition, a distance calculator includes a monocular distance calculation section 203 , a stereo distance calculation section 204 , a blurriness level calculation section 201 , a distance estimation section 202 , and an output distance calculation section 206 . The monocular distance calculation section 203 calculates the distance to a target based on image information captured by a camera 101 or 102 . The stereo distance calculation section 204 calculates the distance to the target based on image information captured by the two cameras 101 and 102 . The blurriness level calculation section 201 calculates the blurriness level of the image information captured by the image information captured by the cameras 101 and 102 . The distance estimation section 202 estimates the distance to the target at the time of capturing of images by the cameras 101 and 102 . The output distance calculation section 206 calculates the distance to the target to be output. The output distance calculation section 206 selects, as the distance to be output, the distance calculated by the monocular distance calculation section 203 or the distance calculated by the stereo distance calculation section 204 based on the blurriness level and the estimated distance.
1. A distance calculator for an imaging system having a plurality of imaging devices, the distance calculator comprising:
a first distance calculator circuit, the first distance calculator circuit calculates distance to a target based on image information captured by one of the plurality of imaging devices;
a second distance calculator circuit, the second distance calculator circuit calculates distance to the target based on image information captured by at least two of the plurality of imaging devices;
a blurriness level calculator circuit, the blurriness level calculator circuit calculates a blurriness level of the image information captured by the single imaging device and a blurriness level of the image information captured by the at least two imaging devices;
a distance estimator circuit, the distance estimator circuit estimates distance to the target at the time of capturing of images by the single imaging device and the at least two imaging devices; and
an output distance calculator circuit, the output distance calculator circuit calculates distance to the target to be output, wherein
the output distance calculator circuit selects a first distance calculated by the first distance calculator circuit as the distance to be output when the distance estimated by the distance estimator circuit is lower than a predetermined distance threshold and when the blurriness level calculated by the blurriness level calculator circuit is lower than a predetermined blurriness threshold;
the output distance calculator circuit selects a second distance calculated by the second distance calculator circuit as the distance to be output when the distance estimated by the distance estimator circuit is lower than the predetermined distance threshold and when the blurriness level calculated by the blurriness level calculator circuit is higher than the predetermined blurriness threshold; and
the output distance calculator circuit selects the second distance calculated by the second distance calculator circuit as the distance to be output when the distance estimated by the distance estimator circuit is higher than the predetermined distance threshold.
2. The distance calculator of claim 1 , wherein
the first distance calculator circuit calculates distance to the target based on the image information having the smallest blurriness level of the image information captured by the single imaging device and the image information captured by the at least two imaging devices.
3. The distance calculator of claim 1 , wherein
the second distance calculator circuit has a plurality of distance calculation means adapted to calculate the distance to the target based on the image information captured by the at least two imaging devices.
4. The distance calculator of claim 3 further comprising:
a distance selector, the distance selector selects one of the plurality of distance calculation means based on the blurriness levels calculated by the blurriness level calculator circuit and the distance estimated by the distance estimator circuit.
5. A distance calculation method of an imaging system having a plurality of imaging devices, the distance calculation method comprising:
calculating a first distance to a target based on image information captured by one of the plurality of imaging devices;
calculating a second distance to the target based on image information captured by at least two of the plurality of imaging devices;
calculating blurriness level of the image information captured by the single imaging device and that of the image information captured by the at least two imaging devices;
estimating distance to the target at the time of capturing of images by the single imaging device and the at least two imaging devices; and
selecting, as distance to the target to be output:
the first distance when the estimated distance is lower than a predetermined distance threshold and when the blurriness level is lower than a predetermined blurriness threshold;
the second distance when the estimated distance is lower than the predetermined distance threshold and when the blurriness level is higher than the predetermined blurriness threshold; or
the second distance when the estimated distance is higher than the predetermined distance threshold.