A method of detecting a moving object in an image signal comprising a plurality of sequential image frames of a plurality of pixels (P), the method comprising, for each image frame: receiving, for each pixel (P) in the frame, a corresponding motion map pixel (MP) set to either a first motion value (FMV) or a second motion value (SMV) indicating that the pixel (P) is associated or is not associated, respectively, with an object in the image frame that is in motion with respect to a background; assigning a group count value (GCV) to each motion map pixel (MP) as a function of the motion values of adjacent motion map pixels; maintaining an indexed grouping table comprising the outermost pixel coordinates (Y_Start, Y_Stop, X_Start, X_Stop) of the boundary pixels for each group of pixels having a same group count value (GCV) and information representing two groups of pixels having different group count values adjacent to one another; determining if two different groups of pixels having different group count values are adjacent to one another by comparing the group count value (GCV) for each respective motion map pixel MP to the GCVs of two adjacent motion map pixels and, if so determined, updating the outermost pixel coordinates of the group count value for the adjacent motion map pixel in the indexed grouping table; maintaining a multiple link table to represent when one group count value is adjacent to multiple other group count values, including information identifying two motion map pixels having a same group count value GCV adjacent to two other motion map pixels each having a different group count value GCV; traversing the indexed grouping table and the multiple link table and determining pixel coordinates for a boundary that encompasses two or more adjacent groups of pixels having different group count values; and forwarding the boundary pixel coordinates to an object tracking system. receiving, for each pixel (P) in the frame, a corresponding motion map pixel (MP) set to either a first motion value (FMV) or a second motion value (SMV) indicating that the pixel (P) is associated or is not associated, respectively, with an object in the image frame that is in motion with respect to a background; assigning a group count value (GCV) to each motion map pixel (MP) as a function of the motion values of adjacent motion map pixels; maintaining an indexed grouping table comprising the outermost pixel coordinates (Y_Start, Y_Stop, X_Start, X_Stop) of the boundary pixels for each group of pixels having a same group count value (GCV) and information representing two groups of pixels having different group count values adjacent to one another; determining if two different groups of pixels having different group count values are adjacent to one another by comparing the group count value (GCV) for each respective motion map pixel MP to the GCVs of two adjacent motion map pixels and, if so determined, updating the outermost pixel coordinates of the group count value for the adjacent motion map pixel in the indexed grouping table; maintaining a multiple link table to represent when one group count value is adjacent to multiple other group count values, including information identifying two motion map pixels having a same group count value GCV adjacent to two other motion map pixels each having a different group count value GCV; traversing the indexed grouping table and the multiple link table and determining pixel coordinates for a boundary that encompasses two or more adjacent groups of pixels having different group count values; and forwarding the boundary pixel coordinates to an object tracking system. <EOS>