Object detection device, device control system, and medium

1. An object detection device, comprising:

processing circuitry configured to

generate, based on a distance image that includes a distance for each pixel that is defined by a horizontal coordinate along a horizontal axis and a vertical coordinate along a vertical axis, a first map in which a first axis is the horizontal axis of the distance image and a second axis is the distance, and a second map in which the first axis is the horizontal axis of the distance image and the second axis is the distance, the second map having a lower resolution than the first map, and the first and second maps being different from the distance image; and

determine an object using information in the first map when a location of the object along the second axis is determined to be within a first distance range, and determine the object using information in the second map when the location of the object is determined to be within a second distance range different from the first distance range.

2. The object detection device as claimed in claim 1 , wherein the processing circuitry is further configured to determine the object using the second distance range, which includes distances greater than those in the first distance range.

3. The object detection device as claimed in claim 1 , wherein the processing circuitry is further configured to generate the second map by thinning out pixels in the horizontal direction of the first map.

4. The object detection device as claimed in claim 1 , wherein the processing circuitry is further configured to merge a first detection result determined using the first map with a second detection result determined using the second map by selecting the first detection result when the location is within the first distance range, and selecting the second detection result when the location is within the second distance range.

5. The object detection device of claim 1 , wherein the processing circuitry is further configured to detect a first candidate object using the first map, detect a second candidate object using the second map, the second candidate object corresponding to the first candidate object, and determine the object to be one of the first and second candidate objects, based on a location of the first and second candidate objects and the first and second distance ranges.

6. The object detection device of claim 1 , wherein each particular pixel of the first map generated by the processing circuitry represents a frequency of a particular distance occurring at a particular horizontal position, the particular pixel of the first map being located at coordinates given by the particular horizontal position and the particular distance.

7. The object detection device of claim 1 , wherein the processing circuitry is further configured to generate the distance image, which is a parallax image generated from brightness image data output from a stereo camera.

8. A device control system, comprising:

processing circuitry configured to

generate, based on a distance image that includes a distance for each pixel that is defined by a horizontal coordinate along a horizontal axis and a vertical coordinate along a vertical axis, a first map in which a first axis is the horizontal axis of the distance image and a second axis is the distance, and a second map in which the first axis is the horizontal axis of the distance image and the second axis is the distance, the second map having a lower resolution than the first map, and the first and second maps being different from the distance image;

determine an object using information in the first map when a location of the object along the second axis is determined to be within a first distance range, and determine the object using information in the second map when the location of the object is determined to be within a second distance range different from the first distance range; and

a controller configured to control a predetermined device based on the determined object.

9. An imaging device, comprising:

the object detection device as claimed in claim 1 ; and

two imaging units, outputs of which are used to generate the distance image.

10. A moving object comprising:

the device control system as claimed in claim 8 ,

wherein the moving object is controlled by the controller.

11. A non-transitory computer-readable recording medium having a program stored therein for causing a computer to execute a process, the process comprising:

generating, based on a distance image that includes a distance for each pixel that is defined by a horizontal coordinate along a horizontal axis and a vertical coordinate along a vertical axis, a first map in which a first axis is the horizontal axis of the distance image and a second axis is the distance, and a second map in which the first axis is the horizontal axis of the distance image and the second axis is the distance, the second map having a lower resolution than the first map, and the first and second maps being different from the distance image; and

determining an object using information in the first map when a location of the object along the second axis is determined to be within a first distance range, and determining the object using information in the second map when the location of the object is determined to be within a second distance range different from the first distance range.