Spectral Synthesis for Image Capture Device Processing

摘要

A substantially rectangular spectral representation is synthesized, which is adapted to produce image capture device sensor outputs if applied to an image capture device. The synthesized substantially rectangular spectral representation can be utilized in generating output color values of an output color space from image capture device sensor outputs, where the image capture device sensor outputs correspond to an image captured by an image capture device. The generated output color values correspond to colors perceived by the human visual system for the same image as that captured by the image capture device. Image capture device gamut is also determined.

主权项

1. A method for synthesizing a substantially rectangular spectral representation of a plurality of image capture device sensor outputs, the plurality of image capture device sensor outputs being a result of an input spectrum of an image being applied to a corresponding plurality of image capture device spectral sensitivities of an image capture device, the method comprising:
providing the plurality of image capture device sensor outputs; determining a first wavelength and a second wavelength of the substantially rectangular spectral representation based on the plurality of image capture device sensor outputs; wherein the determining of the first wavelength and the second wavelength comprises: dividing two of the image capture device sensor outputs by the sum of all of the image capture device sensor outputs; and using a two-dimensional look-up table to map results of the dividing to determine the first wavelength and the second wavelength; and computing a scale factor based on any one of the image capture device sensor outputs and its corresponding image capture device spectral sensitivity to synthesize the substantially rectangular spectral representation based on the plurality of image capture device sensor outputs, wherein the computing of the scale factor comprises: performing a circular integration of an image capture device spectral sensitivity across an interval defined by the first wavelength and the second wavelength of the substantially rectangular spectral representation, wherein the image capture device spectral sensitivity is associated with a corresponding image capture device sensor output from among the plurality of image capture device sensor outputs; and dividing the associated corresponding image capture device sensor output by a result of the circular integration to compute the scale factor; wherein:
the synthesized substantially rectangular spectral representation is adapted to produce the plurality of image capture device sensor outputs if applied to the image capture device, andthe first wavelength comprises a wavelength where the substantially rectangular spectral representation transitions from zero to the scale factor and the second wavelength comprises a wavelength where the substantially rectangular spectral representation transitions from the scale factor to zero.