Method for learning network parameter of neural network, method for calculating camera parameter, and computer-readable recording medium recording a program

A method for learning a network parameter of a neural network, the method comprising, by an information processor:

• acquiring a learning image;
• acquiring a true camera parameter related to the learning image;
• calculating a true two-dimensional coordinate point by projecting a three-dimensional coordinate point on a unit spherical surface onto a predetermined plane by using the true camera parameter;
• calculating an estimated three-dimensional coordinate point by projecting the true two-dimensional coordinate point onto the unit spherical surface by using the estimated camera parameter estimated by the neural network;
• and
• learning the network parameter of the neural network based on a distance between the three-dimensional coordinate point and the estimated three-dimensional coordinate point.

A computer-readable recording medium recording a program that causes an information processor to function as:

• acquisition means;
• and
• calculation means,
• the acquisition means
• acquires a learning image;
• and
• acquires a true camera parameter regarding the learning image, and
• the calculation means
• calculates a true two-dimensional coordinate point by projecting a three-dimensional coordinate point on a unit spherical surface onto a predetermined plane using the true camera parameter;
• calculates an estimated two-dimensional coordinate point by projecting the three-dimensional coordinate point onto the predetermined plane using the estimated camera parameter estimated by a neural network;
• and
• learning a network parameter of the neural network based on a distance between the true two-dimensional coordinate point and the estimated two-dimensional coordinate point.

A computer-readable recording medium recording a program that causes an information processor to function as:

• acquisition means;
• and
• calculation means,
• the acquisition means
• acquires a learning image;
• and
• acquires a true camera parameter regarding the learning image;
• and
• the calculation means
• calculates a true two-dimensional coordinate point by projecting a three-dimensional coordinate point on a unit spherical surface onto a predetermined plane using the true camera parameter;
• calculates an estimated three-dimensional coordinate point by projecting the true two-dimensional coordinate point on the unit spherical surface using an estimated camera parameter estimated by a neural network;
• and
• learns a network parameter of the neural network based on a distance between the three-dimensional coordinate point and the estimated three-dimensional coordinate point.