Abstract: Cameras 31, 32 take images of an image space around a door. A distance calculation unit 33 calculates the distance to an object in the taken images. A coordinate transformation unit 34 detects the three-dimensional position of the object in the image space. The image space covered by the cameras 31, 32 is divided into a plurality of voxels. Some of these voxels are optionally set as constituents of the detection area. A judgement unit 36 judges whether the detected three-dimensional position of the object locates within or outside the detection area. If the object is present within the detection area, an output unit 37 produces an object detection signal, so that the door is allowed to open.

Abstract: Cameras 31, 32 take images of an image space around a door. A distance calculation unit 33 calculates the distance to an object in the taken images. A coordinate transformation unit 34 detects the three-dimensional position of the object in the image space. The image space covered by the cameras 31, 32 is divided into a plurality of voxels. Some of these voxels are optionally set as constituents of the detection area. A judgement unit 36 judges whether the detected three-dimensional position of the object locates within or outside the detection area. If the object is present within the detection area, an output unit 37 produces an object detection signal, so that the door is allowed to open.