A LiDAR detection system, comprising: a plurality of optical sources disposed along a first direction for transmitting a respective plurality of transmitted optical signals into a region; a scanning device for scanning the plurality of transmitted optical signals over a second direction different than the first direction; a receiver for receiving reflected optical signals generated by reflection of the transmitted optical signals and generating receive signals indicative of the reflected optical signals, wherein the receiver comprises a 2-dimensional array of optical detectors; a mask disposed in proximity to the receiver between the region and the receiver, the mask comprising a plurality of optically transparent slits such that at least a substantial portion of the reflected optical signals pass through the slits, and an optically opaque portion adjacent to the slits, such that the optically opaque portion of the mask substantially blocks ambient light from reaching the receiver; and a processor coupled to the receiver for receiving the receive signals and processing the receive signals to generate detections of one or more objects in the region; wherein the plurality of slits in the mask are disposed along a direction aligned with a first dimension of the array of optical detector; wherein the receive signals are generated for a set of detectors in the array disposed along the first dimension of the array and aligned with the slits in the mask and exposed to the received optical signals; and wherein the receive signals are generated for one set of detectors at a time, the sets of detectors being offset with respect to each other along a second dimension of the array of optical detectors substantially orthogonal to the first dimension of the array of optical detectors. a plurality of optical sources disposed along a first direction for transmitting a respective plurality of transmitted optical signals into a region; a scanning device for scanning the plurality of transmitted optical signals over a second direction different than the first direction; a receiver for receiving reflected optical signals generated by reflection of the transmitted optical signals and generating receive signals indicative of the reflected optical signals, wherein the receiver comprises a 2-dimensional array of optical detectors; a mask disposed in proximity to the receiver between the region and the receiver, the mask comprising a plurality of optically transparent slits such that at least a substantial portion of the reflected optical signals pass through the slits, and an optically opaque portion adjacent to the slits, such that the optically opaque portion of the mask substantially blocks ambient light from reaching the receiver; and a processor coupled to the receiver for receiving the receive signals and processing the receive signals to generate detections of one or more objects in the region; wherein the plurality of slits in the mask are disposed along a direction aligned with a first dimension of the array of optical detector; wherein the receive signals are generated for a set of detectors in the array disposed along the first dimension of the array and aligned with the slits in the mask and exposed to the received optical signals; and wherein the receive signals are generated for one set of detectors at a time, the sets of detectors being offset with respect to each other along a second dimension of the array of optical detectors substantially orthogonal to the first dimension of the array of optical detectors.