Method and apparatus for measuring response curve of an image sensor

An apparatus for measuring a response curve of an image sensor, comprising:

• a shooting unit configured to take a single photograph of a Grey Scale card with an image sensor to be measured, wherein said Grey Scale card is a reflective Grey Scale card or a transmissive Grey Scale card, said Grey Scale card has a plurality of grayscale blocks, each greyscale block having a uniform greyscale, different greyscale blocks having different greyscales, a reflectivity or a transitivity of each greyscale block on said Grey Scale card is marked, and said single photograph comprises a plurality of greyscale image blocks respectively corresponding to said greyscale blocks;
• a relative exposure value calculating unit configured to calculate a relative exposure value for each greyscale image block of said single photograph, wherein said relative exposure value is a product of an exposure time with which a corresponding photograph is taken and said greyscale of corresponding greyscale block, said greyscale of the greyscale block is represented by its reflectivity or transitivity;
• a reference point setting unit configured to plot a plurality of reference points based on said pixel values of pixel points within each greyscale image block and said relative exposure values of said greyscale image blocks, wherein said pixel values are defined as an ordinate data and said relative exposure values are defined as an abscissa data;
• and
• an interpolation calculation unit configured to execute an interpolation calculation based on said plurality of reference points, to obtain a response curve of said image sensor, wherein said relative exposure value calculating unit, said reference point setting unit and said interpolation calculation unit are implemented using a processor.