Method and apparatus for determining exposure setting

An image capturing device comprising:

• an image sensor arranged to capture image frames;
• a memory storing an exposure value;
• an exposure controller arranged to control the exposure of the image to be captured by the image sensor based on the exposure value stored in the memory;
• a processing unit arranged to determine a first exposure value by finding an exposure value that results in a substantially optimum value when applied to a total cost calculation, wherein the calculating of said total cost from a specific exposure value is based on signal levels at the specific exposure value of image pixels in the captured image frame combined with a cost function;
• a saturated pixels cost calculator arranged to calculating a saturated pixels cost related to the saturated pixels for the captured image at the first exposure value;
• the processing unit further arranged to determine a second exposure value by finding a decrease in exposure value, in relation to the first exposure value, for which decrease in exposure value a change in total cost for non-saturated pixels, in relation to the total cost for non-saturated pixels at the first exposure value, is substantially equal to the saturated pixel cost calculated at the first exposure value;
• and
• storing the second exposure value in memory as the exposure value.