Detection apparatus, detection method, and conveyance system

1 . A detection apparatus comprising a processor configured to:

acquire height information at a plurality of points in a subject corresponding to one or more physical objects while the one or more physical objects are being conveyed by a conveyance mechanism;

determine, based on the height information, whether one or more steps are present at respective measurement locations, each step corresponding to difference between height information at spatially distinct portions of the subject that is a height equal to or higher than a predetermined height from a reference in the subject;

detect that the subject is in a state in which a plurality of the one or more physical objects are overlapped, if a number of the steps determined at the respective measurement locations is equal to or greater than a first threshold value; and

control an excluding mechanism associated with the conveyance mechanism such that, in response to detecting feeding of a single object of the one or more physical objects, the single object is fed in a direction toward a downstream side of the conveyance mechanism, and in response to detecting overlapped feeding of a plurality of the one or more physical objects, the plurality of the one or more physical objects are fed in a direction different from the downstream side.

2 . The apparatus according to claim 1 , wherein the processor is further configured to:

detect whether each of a first area and a second area set in the subject based on the height information forms a plane; and

determine that the steps are present, if it is detected that a first plane is formed in the first area and a second plane is formed in the second area, and if a difference in height between the first plane and the second plane is greater than a second threshold value.

3 . The apparatus according to claim 2 , wherein the processor is further configured to determine that no step is present, if the difference in height between the first plane and the second plane is equal to or smaller than the second threshold value.

4 . The apparatus according to claim 2 , wherein the processor is further configured to:

calculate a first regression plane of the first plane and a second regression plane of the second plane; and

determine that no step is present, if a first vector is identical in direction to a second vector, the first vector being a vector which, on an assumption that the second regression plane is extended to the first area, is directed from a point on the second regression plane in the first area to the first regression plane at a shortest distance, the second vector being a vector which, on an assumption that the first regression plane is extended to the second area, is directed from a point on the first regression plane in the second area to the second regression plane at a shortest distance.

5 . The apparatus according to claim 4 , wherein the processor is further configured to determine that the steps are present, if the first vector and the second vector are different in direction.

6 . The apparatus according to claim 2 , wherein the processor is further configured to:

calculate a first regression plane of the first plane and a second regression plane of the second plane; and

determine that the steps are present if a value obtained by subtracting a result of multiplying a sum of a regression error of the first regression plane and a regression error of the second regression plane by a first value from a difference in height relating to the first regression plane and the second regression plane is greater than the second threshold value.

7 . The apparatus according to claim 2 , wherein the first area and the second area are rectangular, and

the processor is further configured to determine whether or not the steps are present, using at least one of:

a first determination result of determining whether or not the plane is present in each of the first area and the second area arranged in a vertical direction;

a second determination result of determining whether or not the plane is present in each of the first area and the second area arranged in a transverse direction; and

a third determination result of determining whether or not the plane is present in each of the first area and the second area arranged in a slanting direction.

8 . The apparatus according to claim 1 , wherein the processor is further configured to;

detect whether each of a first area and a second area set in the subject based on the height information forms a plane; and

determine that no step is present, if it is detected that at least one of the first area and the second area forms no plane.

9 . The apparatus according to claim 1 , wherein the processor is further configured to detect that the subject is in a state in which a plurality of the one or more physical objects are overlapped, if the number of steps is equal to or greater than the first threshold value and if a plurality of steps are spatially adjacent.

10 . The apparatus according to claim 1 , wherein the processor is further configured to detect that the subject is a single object, if the number of steps is smaller than the first threshold value or if the number of steps is equal to or greater than the first threshold value and the steps are not spatially adjacent.

11 . A conveyance system comprising the detection apparatus according to claim 1 , the conveyance mechanism configured to convey objects, and the excluding mechanism.

12 . A detection method comprising:

acquiring height information at a plurality of points in a subject corresponding to one or more physical objects while the one or more physical objects are being conveyed by a conveyance mechanism;

determining, based on the height information, whether or not one or more steps are present at respective measurement locations, each step corresponding to a height difference between height information at spatially distinct portions of the subject that is equal to or higher than a predetermined height from a reference in the subject;

detecting that the subject is in a state in which a plurality of the one or more physical objects are overlapped, if a number of the steps determined at the respective measurement locations is equal to or greater than a first threshold value; and

controlling an excluding mechanism associated with the conveyance mechanism such that, in response to detecting feeding of a single object of the one or more physical objects, the single object is fed in a direction toward a downstream side of the conveyance mechanism, and in response to detecting overlapped feeding of a plurality of the one or more physical objects, the plurality of the one or more physical objects are fed in a direction different from the downstream side.