Image processing apparatus

摘要

An image processing apparatus includes an image input unit for inputting color image data, a first color conversion unit for converting the inputted color image data into first image data of the L*a*b color space having independently brightness component and chromaticity component, a background detection unit for detecting a background color component from the converted first image data of the L*a*b color space, a background removing unit for converting, based on a white value conversion parameter derived based on a ratio of the background color corresponding to the background component to a prescribed reference white color in the L*a*b color space, the first image data into second image data having the background color in white, a second color conversion unit for converting the second image data of the L*a*b color space into third image data of a prescribed color space, and an output unit for outputting the converted third image data of the prescribed color space.

主权项

1. An image processing apparatus comprising:
an image input unit configured to input color image data; a first color conversion unit configured to convert the input color image data into first image data of an L*a*b color space having independent brightness and chromaticity components; a background color detection unit configured to detect a background color component, Lws, aws, bws, from the converted first image data of the L*a*b color space by:
producing an L value histogram (histogram [L]) indicating brightness from the converted first image data,retrieving a summation, sum a[L], of an a* value of each L value and a summation, sum b[L], of a b* value of each L value,detecting a peak start brightness, start L,detecting a peak brightness, top L,seeking a background brightness, Lws, by the peak start brightness, start L, the peak brightness, top L, and a formula,
Lws=top—L−(start—L−top—L), andseeking chromaticity aws, bws by formulas,aws=∑l=Lwsstart_L⁢sum_a⁡[l]∑l=Lwsstart_L⁢histogram⁡[l],bws=∑l=Lwsstart_L⁢sum_b⁡[l]∑l=Lwsstart_L⁢histogram⁡[l],  respectively; a background removing unit configured to convert, based on a white value conversion parameter derived based on a ratio of the background color corresponding to the background color component to a prescribed reference white color in the L*a*b color space, the first image data into second image data having the background color in white; a second color conversion unit configured to convert the second image data of the L*a*b color space into third image data of a prescribed color space; and an output unit configured to output the converted third image data of the prescribed color space.