a segmentation operation is applied to an input image to identify foreground objects of interest , and then a shadow removal operation is applied to remove any detected shadows from the foreground segmentation . the shadow removal algorithms can leave holes and bisections in the segmentation map , however , which will then subsequently impact on an object detection step performed using connected component analysis . to get around this problem , a conditional morphological dilation operation is applied to the segmentation map to ‘ grow ’ the segmented blobs to fill in any holes and bisections , without re - growing shadow pixels in the segmentation . the result is an object detection method and system which is robust to illumination changes causing shadows and / or highlights .