Methods and systems are described for processing an image captured with an image sensor, such as a camera. In one embodiment, an estimated ambient light level of the captured image is determined and used to compute an optical-optical transfer function (OOTF) that is used to correct the image to preserve an apparent contrast of the image under the estimated ambient light level in a viewing environment. The estimated ambient light level is determined by scaling pixel values from the image sensor using a function that includes exposure parameters and a camera specific parameter derived from a camera calibration.