Distance estimation device, distance estimation method, and distance estimation computer program

A distance estimation method comprising:

• detecting a predetermined object represented in an image acquired by a camera;
• calculating, by inputting the image to a classifier that calculates a confidence score representing likelihood that, for each of a plurality of types of the predetermined object, the detected object belongs to the type, a size of the detected object and the confidence score for each of the plurality of types;
• estimating a size in the real space of the detected object by weighted-averaging, for each of the plurality of types, a reference size in the real space of the type being stored in a memory by the confidence score of the type;
• and
• estimating a distance to the detected object, based on a ratio between the size of the detected object on the image and an estimated size of the detected object on the image when a distance to the detected object is a predetermined reference distance, which corresponds to the estimated size in the real space of the detected object.

A non-transitory recording medium in which a distance estimation computer program is recorded for causing a computer to execute:

• detecting a predetermined object represented in an image acquired by a camera, and calculating, by inputting the image to a classifier that calculates a confidence score representing likelihood that, for each of a plurality of types of the predetermined object, the detected object belongs to the type, a size of the detected object and the confidence score for each of the plurality of types;
• estimating a size in the real space of the detected object by weighted-averaging, for each of the plurality of types, a reference size in the real space of the type being stored in a memory by the confidence score of the type;
• and
• estimating a distance to the detected object, based on a ratio between the size of the detected object on the image and an estimated size of the detected object on the image when a distance to the detected object is a predetermined reference distance, which corresponds to the estimated size in the real space of the detected object.