Monitoring system, monitoring apparatus, and monitoring method

1 . A monitoring system comprising:

at least one memory storing instructions, and

at least one processor configured to execute the instructions to;

acquire three-dimensional data output from a three-dimensional ranging sensor for scanning a paved surface for aircraft using laser light;

extract, from the three-dimensional data, real image data about a real image present on the paved surface and mirage image data about a mirage image corresponding to the real image; and

detect a foreign object left on the paved surface using the real image data and the mirage image data.

2 . The monitoring system according to claim 1 , wherein

the three-dimensional ranging sensor is a three-dimensional LiDAR scanner,

the three-dimensional data is point cloud data,

the real image data is real image point cloud data, and

the mirage image data is mirage image point cloud data.

3 . The monitoring system according to claim 2 , wherein the at least one processor is further configured to execute the instructions to determine, when the number of measuring points constituting one image is greater than or equal to a predetermined value, that there is a foreign object corresponding to the one image and to determine, when the number of measuring points constituting one image is less than the predetermined value, that there is no foreign object corresponding to the one image, and

the at least one processor is further configured to execute the instructions to generate one combined image from a plurality of measuring points indicated by the real image point cloud data and a plurality of measuring points indicated by the mirage image point cloud data and performs the detection of the foreign object.

4 . The monitoring system according to claim 2 , wherein the at least one processor is further configured to execute the instructions to synthesize the real image point cloud data and the mirage image point cloud data by vertically inverting the mirage image and then superimposing the vertically-inverted mirage image onto the real image, thereby generating synthetic point cloud data, and

the at least one processor is further configured to execute the instructions to perform detection of the foreign object based on the synthetic point cloud data.

5 . The monitoring system according to claim 4 , wherein the at least one processor is further configured to execute the instructions to estimate a type of the detected foreign object based on the synthetic point cloud data when performing the detection of the foreign object based on the synthetic point cloud data.

6 . The monitoring system according to claim 1 , wherein

the paved surface comprises:

a nearby paved surface near the three-dimensional ranging sensor capable of being measured by the three-dimensional ranging sensor; and

a distant paved surface farther from the three-dimensional ranging sensor than the nearby paved surface and not capable of being measured by the three-dimensional ranging sensor, and

the real image and the mirage image are positioned so as to face each other across the distant paved surface.

7 . A monitoring method executed by a computer, the monitoring method comprising:

acquiring three-dimensional data output from a three-dimensional ranging sensor for scanning a paved surface for aircraft using laser light;

extracting, from the three-dimensional data, real image data about a real image present on the paved surface and mirage image data about a mirage image corresponding to the real image; and

detecting a foreign object left on the paved surface using the real image data and the mirage image data.

8 . The monitoring method according to claim 7 , wherein

the three-dimensional ranging sensor is a three-dimensional Lidar scanner,

the three-dimensional data is point cloud data,

the real image data is real image point cloud data, and

the mirage image data is mirage image point cloud data.

9 . The monitoring method according to claim 8 , wherein

in the detection of the foreign object, when the number of measuring points constituting one image is greater than or equal to a predetermined value, it is determined that there is a foreign object corresponding to the one image and when the number of measuring points constituting one image is less than the predetermined value, it is determined that there is no foreign object corresponding to the one image, and

in the detection of the foreign object, one combined image is generated from a plurality of measuring points indicated by the real image point cloud data and a plurality of measuring points indicated by the mirage image point cloud data and the detection of the foreign object is performed.

10 . The monitoring method according to claim 8 , wherein

in the detection of the foreign object, the real image point cloud data and the mirage image point cloud data are synthesized by vertically inverting the mirage image and then superimposing the vertically-inverted mirage image onto the real image, thereby generating synthetic point cloud data, and

the detection of the foreign object is performed based on the synthetic point cloud data.

11 . The monitoring method according to claim 10 , wherein

in the detection of the foreign object, a type of the detected foreign object is estimated based on the synthetic point cloud data when performing the detection of the foreign object based on the synthetic point cloud data.

12 . The monitoring method according to claim 7 , wherein

the paved surface comprises:

a nearby paved surface near the three-dimensional ranging sensor capable of being measured by the three-dimensional ranging sensor; and

a distant paved surface farther from the three-dimensional ranging sensor than the nearby paved surface and not capable of being measured by the three-dimensional ranging sensor, and

the real image and the mirage image are positioned so as to face each other across the distant paved surface.