Various implementations disclosed herein include devices, systems, and methods implemented by an electronic device with an imaging sensor that includes both an arrangement of first pixels and a plurality of second pixels at or near the perimeter (e.g., in a surrounding rectangle) of the arrangement. In some implementations, the second pixels, which may be larger in size than the arrangement of first pixels, can be intermittently positioned, for example, with intervening space in between groups of one or more second pixels along the side columns, top rows, or bottom rows of the arrangement. In some implementations, detected movement in a physical environment is determined to correspond to a person approaching the electronic device based on data of the second pixels. In some implementations, detecting the person approaching the electronic device initiates a user verification process at the electronic device.