1. An image processing device comprising: an image sensor configured to provide initial sensor image data and final sensor image data; a lens configured to expose an image of a scene onto the image sensor; a processor configured to: process the initial sensor image data to select one of a plurality of pre-determined scene types, wherein the pre-determined scene types include at least one scene type selected from the group including high-contrast scene, low-contrast scene, sky scene, night scene, color-saturated scene, and text/document scene; and cause an exposure control system to adjust the exposure level for a final image according to the selected scene type; and the exposure control system configured to adjust the exposure level for capturing the final image on the image sensor by setting, according to signals from the processor, the exposure level for the final image to be a default scene exposure level changed by a pre-determined relative exposure level corresponding to the selected scene type, where the relative exposure level change is an increase in exposure if the scene type is low-contrast scene, night scene, or text/document scene, and a decrease in exposure if the scene type is high-contrast scene, sky scene, or color-saturated scene.