Camera calibration and automatic adjustment of images

A system comprising:

• one or more computing devices configured to perform operations including:
• extracting line segments from an input image;
• determining initial values for an energy function according to the extracted line segments;
• and
• calibrating camera parameters by iteratively optimizing the energy function to estimate a camera intrinsic parameter matrix, an orientation matrix, and a set of vanishing points for the input image in conjunction with each other.

A device comprising:

• one or more processors;
• one or more computer-readable storage media;
• and
• computer readable instructions stored on the one or more computer-readable storage media which, when executed by the one or more processors, perform operations comprising:
• extracting line segments from an input image;
• determining Manhattan directions based on the extracted line segments;
• determining initial values for an energy function according to the extracted line segments and the Manhattan directions;
• and
• calibrating camera parameters by iteratively optimizing the energy function to estimate, in conjunction with each other:
• a camera intrinsic parameter matrix including assumptions that a focal length in pixel dimension of a camera used to capture the image is the same as a width of the image and that a center of projection is an image center;
• an orientation matrix including assumptions that rotation angles of the orientation matrix approximate zero;
• and
• a set of vanishing points for the input image.