Optical data processing apparatus, optical data processing method and optical data processing program

An optical data processing method comprising:

• a step of obtaining a laser scan point cloud obtained by a laser scanner mounted on a moving body in a moving condition, and image data of a photographed image photographed by a camera mounted on the moving body in a moving condition;
• a step of obtaining Δt when the camera photographs with a delay Δt when the camera is commanded to take a photograph at time T;
• and
• a step of making a projection image, the projection image made by overlapping and projecting a point cloud image in which the laser scan point cloud is viewed from a specific viewpoint and the photographed image in which directions of viewing lines are aligned,
• wherein relationships of exterior orientation elements of the laser scanner and the camera on the moving body are known,
• projection is performed multiple times by changing viewpoint position of at least one of the point cloud image and the photographed image so that multiple projection images are made, and
• Δt is calculated in a condition in which difference in overlapping degree of the point cloud image and the photographed image in the multiple made projection images is minimal or is not greater than a threshold value.

A non-transitory computer recording medium storing computer executable instructions that, when executed by a computer processor, cause the computer processor to perform operations regarding an optical data processing program comprising:

• obtaining a laser scan point cloud obtained by a laser scanner mounted on a moving body in a moving condition and image data of a photographed image photographed by a camera mounted on the moving body in a moving condition,
• obtaining Δt in a case in which the camera photographs with a delay Δt when the camera is commanded to take a photograph at time T, and
• making a projection image, the projection image made by overlapping and projecting a point cloud image in which the laser scan point cloud is viewed from a specific viewpoint and the photographed image in which directions of viewing lines are aligned, wherein
• relationships of exterior orientation elements of the laser scanner and the camera on the moving body are known,
• projection is performed multiple times by changing viewpoint position of at least one of the point cloud image and the photographed image so that multiple projection images are made, and
• Δt is calculated in a condition in which difference in overlapping degree of the point cloud image and the photographed image in the multiple made projection images is minimal or is not greater than a threshold value.