An image processing apparatus includes the following elements. A receiving device receives an image. An extracting device extracts regions from the image received by the receiving device. A selecting device selects a region from among the regions extracted by the extracting device in accordance with a predetermined rule. A measuring device measures luminance values of pixels contained in the region selected by the selecting device. An estimating device estimates a function representing a degree of fog in the image received by the receiving device from the luminance values of the pixels measured by the measuring device. An eliminating device eliminates fog from the image received by the receiving device on the basis of the function estimated by the estimating device.