Image processing method and device

The invention relates to an image processing method and image processing device. The image processing method comprises the following steps: acquiring an input image; separating out a low-frequency component and a high-frequency component of brightness information of the input image; performing transform mapping on the low-frequency component by taking the environmental light brightness and environmental light reference brightness of an environment in which the input image is to be displayed as influence factors to obtain a transformed low-frequency component; and subtracting the environment light brightness from the transformed low-frequency component, and combining the transformed low-frequency component from which the environment light brightness is subtracted with the high-frequency component to generate an output image corresponding to the input image. The input image is processed from the point of image processing to improve the quality of a displayed image, so that more details of the displayed image can be represented correctly under different environmental light at low hardware cost.