System and methods for detecting blockages in images are described. A method may include receiving a plurality of images captured by a camera installed on a vehicle. The method may include identifying one or more candidate blocked regions in the plurality of images. Each of the candidate blocked regions may contain image data caused by blockages in the camera's field-of-view. The method may further include assigning blockage scores to the one or more candidate blocked regions based on region-associations among the one or more candidate blocked regions in the plurality of images. In response to a determination that one of the blockage scores is above a predetermined blockage threshold, the method may include transmitting a blockage alarm signal to the vehicle.