A method in image processing for detection of a change in the scene in an area. The method comprises the steps of recording a digital image of the area using a sensor and transforming the recorded image by an operator. The operator is based on a previous modeling of changes in the lighting in the area and on a modeling of how the sensor depicts the area in grayscale values in the recorded image. The method further comprises the step of comparing the transformed image with a reference image of the area in order to detect a difference that indicates a change in the scene.