An image processing apparatus includes the following elements. A receiving device receives an image. An estimating device estimates, for each of pixels within the image received by the receiving device, on the basis of the received image, an amount of fog, which is a difference between a luminance value of the pixel and an original luminance value of the pixel. A measuring device measures, for each of the pixels within the image received by the receiving device, a luminance value of the pixel. A determining device determines a correction target value for luminance values of pixels of a background portion within the image received by the receiving device. A correcting device corrects the luminance value of each of the pixels measured by the measuring device on the basis of the amount of fog estimated by the estimating device and the correction target value determined by the determining device.