movement and distance detection within a room

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I am building a program that detects/tracks movement within a room and can determine where (quadrant or distance) that movement is within the room. Any suggestions on how this can be accomplished??

Further detail: Say the camera detects a person within the room from their movement when this happens I need to relay information that 1) there is movement (a person) and 2) spatially where they are within the room either by dividing the room into quadrants and relaying the quadrant or relay the distance from the camera (which is stationary).

Thanks!