A multispectral selective reflection Lidar system generates alternating pulses of at least two wavelengths and senses returns for determining the presence of a predetermined material absorbing and reradiating one wavelength as selective reflections, but not the other. The case includes a ring-shaped support portion for supporting the shaft, a motor connected to a transmission for swinging the mirror, and a clutch portion for disengageably engaging with the base. The bandwidth of the image memory is greater than one byte.