Image processing apparatus and method
AssigneeCanon Kabushiki Kaisha
InventorToshiyuki Ishii
Life of this patent
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Abstract
First image data obtained by capturing an image of a subject under a first light condition, and second image data obtained by capturing an image of the subject under a second light condition different from the first light condition are input. The sampling positions of colors used to generate correction parameters are acquired. First color signal values are sampled from the sampling positions in the first image data, and second color signal values are sampled from the sampling positions in the second image data. Correction parameters used to correct the first image data which depends on the first light condition into image data which depends on the second light condition are generated based on the first and second color signal values.
Claims11
An image processing apparatus comprising:
- an input unit configured to input first image data obtained by capturing an image of a subject under a first light condition, and second image data obtained by capturing an image of the subject under a second light condition different from the first light condition;
- an acquisition unit configured to acquire sampling positions of colors used to generate correction parameters;
- a sampling unit configured to sample first color signal values from the sampling positions in the first image data, and to sample second color signal values from the sampling positions in the second image data;
- and
- a generation unit configured to generate correction parameters, used to correct the first image data which depends on the first light condition into image data which depends on the second light condition, based on the first color signal values and the second color signal values,
- wherein the generation unit comprises:
- a first generator configured to generate color correction parameters used to transform the first color signal values into the second color signal values;
- and
- a second generator configured to calculate a first luminance value from the first color signal values, to calculate a second luminance value from a correction value obtained by correcting the first color signal values using the color correction parameters, and to calculate tone correction parameters used to transform the first luminance value into the second luminance value, and
- wherein at least one of the input unit, the acquisition unit, the sampling unit, or the generation unit is implemented at least in part by hardware components of the image processing apparatus.
An image processing method comprising:
- using a processor to perform steps of:
- inputting first image data obtained by capturing an image of a subject under a first light condition;
- inputting second image data obtained by capturing an image of the subject under a second light condition different from the first light condition;
- acquiring sampling positions of colors used to generate correction parameters;
- sampling first color signal values from the sampling positions in the first image data;
- sampling second color signal values from the sampling positions in the second image data;
- and
- generating correction parameters, used to correct the first image data which depends on the first light condition into image data which depends on the second light condition, based on the first color signal values and the second color signal values,
- wherein the generating step comprises steps of:
- generating color correction parameters used to transform the first color signal values into the second color signal values;
- calculating a first luminance value from the first color signal values, to calculate a second luminance value from a correction value obtained by correcting the first color signal values using the color correction parameters;
- and
- calculating tone correction parameters used to transform the first luminance value into the second luminance value.
Dependencies are inferred from the claim text.