The present invention concerns a method and camera for obtaining a high-contrast image of a predetermined target present in an area under observation. The method involves obtaining an in-band image of the observation area including the target using a filter whose bands are aligned with selected characteristic wavelength bands of the target and an out-of-band image of the observation area excluding the target using the filter with its bands non-aligned with the selected characteristic wavelength bands of the target. Processing of the in-band and out-of-band images results in a high-contrast image highlighting the presence of the target in the observation area and thereby allowing its detection and monitoring.