A method of point source target detection for multispectral imaging is disclosed. In one embodiment, a background source spectral ratio is determined using at least one radiant source, such as baseline intensities, camera optics sensitivity properties and atmospheric transmission properties. Further, a spectral difference is computed for each pixel in an incoming frame by applying the background source spectral ratio to a spectral band-specific radiant intensity value of each pixel. Furthermore, offset biasing in the incoming frame is removed by applying spatial median filtering to each computed spectral difference in the incoming frame.