A system includes a first sensor and a sensor client. During an initial time interval, the sensor client receives top-view images generated by the first sensor and detects contours in the images. The sensor client determines, based on the contours, regions of the top-view images generated by the first sensor to exclude during object tracking. During a subsequent time interval, the sensor client receives a second top-view image generated by the first sensor and detects a contour in the image. The sensor client determines pixel coordinates of the second contour and determines whether at least a threshold percentage of the second pixel coordinates overlap with the region to exclude during object tracking. If at least the threshold percentage of the second pixel coordinates overlap with the region to exclude, a position for tracking the second contour is not determined.