Method and camera for providing an estimation of a mean signal to noise ratio value for an image

A non-transitory computer-readable recording medium having recorded thereon a program that when executed by a device with processing capabilities, performs the following steps:

• providing an image histogram divided into bins, the image histogram comprising information regarding the distribution of pixel values among the image pixels of the output image, each bin comprising a set of image pixels having pixels values within a predetermined range;
• attributing a signal to noise ratio value for each bin of the image histogram;
• weighting, for each bin of the image histogram, the signal to noise ratio value of that bin with the number of image pixels in the set of image pixels of that bin;
• summing the weighted signal to noise ratio values of the bins;
• and
• dividing the sum of weighted signal to noise ratio values of the bins by the total number of image pixels of the output image or the total number of image pixels in the bins of the image histogram.

A camera arranged for providing an estimation of a mean signal to noise ratio value for an output image having a number of image pixels wherein each image pixel of the image has a pixel value, the camera comprising:

• an image sensor being arranged to capture pixel values used to derive pixel values of the image pixels of the output image;
• an image histogram provider being arranged to provide an image histogram comprising information regarding the distribution of pixel values among the image pixels of the output image, each bin of the image histogram comprises a set of image pixels having pixels values within a predetermined range;
• a signal to noise ratio value attributor being arranged to attribute a signal to noise ratio value for each bin of the image histogram;
• and
• a calculator being arranged to calculate the mean signal to noise ratio value by weighting, for each bin of the image histogram, the signal to noise ratio value of that bin with the number of image pixels in the set of image pixels of that bin, summing the weighted signal to noise ratio values of the bins, and dividing the sum of weighted signal to noise ratio values of the bins by the total number of image pixels of the output image or the total number of image pixels in the bins of the image histogram.