Calibration method, calibration device, and computer program product

A calibration system for calibrating a stereo camera including a first camera and a second camera located in a position apart from the first camera by a predetermined distance, and configured to calculate distance information, the calibration system comprising:

• processing circuitry configured to:
• calculate a first correction parameter based on a photographic image acquired by photographing an object with the first camera without interposing a first transparent body, and a photographic image acquired by photographing the object through the first transparent body with the first camera;
• calculate a second correction parameter based on a photographic image acquired by photographing the object with the second camera without interposing the first transparent body, and a photographic image acquired by photographing the object through the first transparent body with the second camera, in a state where a positional relation between the first camera and the first transparent body is the same as in calculating the first correction parameter, and the first camera and the second camera are apart from each other by the predetermined distance;
• and
• calculate a third correction parameter for correcting a relative positional deviation in a parallax, the relative positional deviation affecting calculation of the distance information, in a state where the first camera and the second camera are apart from each other by the predetermined distance, based on a first corrected image obtained by correcting, with the first correction parameter, a photographic image acquired by photographing an object through a second transparent body with the first camera, and a second corrected image obtained by correcting, with the second correction parameter, a photographic image acquired by photographing the object through the second transparent body with the second camera.

A non-transitory computer-readable medium storing a program that causes a computer for calibrating a stereo camera including a first camera and a second camera located in a position apart from the first camera by a predetermined distance, and configured to calculate distance information, to perform a method comprising:

• calculating a first correction parameter based on a photographic image acquired by photographing an object with the first camera without interposing a first transparent body, and a photographic image acquired by photographing the object through the first transparent body with the first camera;
• calculating a second correction parameter based on a photographic image acquired by photographing the object with the second camera without interposing the first transparent body, and a photographic image acquired by photographing the object through the first transparent body with the second camera, in a state where a positional relation between the first camera and the first transparent body is the same as in calculating the first correction parameter, and the first camera and the second camera are apart from each other by the predetermined distance;
• and
• calculating a third correction parameter for correcting a relative positional deviation in a parallax, the relative positional deviation affecting calculation of the distance information, in a state where the first camera and the second camera are apart from each other by the predetermined distance, based on a first corrected image obtained by correcting, with the first correction parameter, a photographic image acquired by photographing an object through a second transparent body with the first camera, and a second corrected image obtained by correcting, with the second correction parameter, a photographic image acquired by photographing the object through the second transparent body with the second camera.