A distance evaluation method for evaluating distances from an observation point to objects within an arbitrary detectable range in a scene is disclosed. The method includes the following steps. First, a focus distance is set to correspond to a lower or higher limit of a chosen detection range. Next, an image is then captured with an image acquisition system, wherein transfer function of the image acquisition system depends on the focus distance. The captured image of the scene is segmented. A blur metric is computed for each image segment of the captured image. The blur metric is associated with the distance of the objects from the observation point in each image segment.