Pixel correction method

A method for correcting defective pixels (19) of an image sensor (17), the image sensor having a plurality of pixels (19) for generating respective exposure dependent pixel signals, wherein for each pixel (19) a respective defect characteristic is associated with the image sensor (17) and comprises information on at least whether the pixel (19) is unusable, can be used without requiring correction or corresponds to one of a plurality of predefined defect classes,

• wherein the method comprises the steps of:
• before the generation of the pixel signals:
• determining for each pixel (19) the respective defect characteristic associated with the image sensor (17) and storing the respective defect characteristic in a memory device (23);
• before making a determination of whether the generated pixel signal of the pixel (19) should be corrected:
• reading the respective defect characteristic out of the memory device (23);
• after the generation of the pixel signals:
• at least for each pixel (19) whose respective defect characteristic does not correspond to an unusable pixel (19) or to a pixel (19) which can be used without requiring correction, making a determination of whether the generated pixel signal of the pixel (19) should be corrected, wherein the determination depends on at least the corresponding defect class of the pixel (19) and on pixel signals of a plurality of adjacent pixels (19);
• and
• replacing the generated pixel signal of the pixel (19) with a replacement value if the making the determination yields the result that the generated pixel signal of the pixel (19) should be corrected.

A digital camera (11) comprising:

• an image sensor (17) which has a plurality of pixels (19) for generating respective exposure dependent pixel signals;
• a memory device (23) in which for each pixel (19) a respective defect characteristic is stored which comprises information on at least whether the pixel (19) is unusable, can be used without requiring correction or corresponds to one of a plurality of predefined defect classes;
• and
• a correction device (21) which is adapted to carry out a method for correcting defective pixels (19) of the image sensor (17);
• the method comprising the steps of:
• before making a determination of whether the generated pixel signal of the pixel (19) should be corrected:
• reading the respective defect characteristic out of the memory device (23);
• after the generation of the pixel signals:
• at least for each pixel (19) whose respective defect characteristic does not correspond to an unusable pixel (19) or to a pixel (19) which can be used without requiring correction, making a determination of whether the generated pixel signal of the pixel (19) should be corrected, wherein the determination depends on at least the corresponding defect class of the pixel (19) and on pixel signals of a plurality of adjacent pixels (19);
• and
• replacing the generated pixel signal of the pixel (19) with a replacement value if the determination yields the result that the generated pixel signal of the pixel (19) should be corrected.