IMAGING LIDAR SYSTEM EMPLOYING MULTIPULSE SINGLE AND MULTIPLE GATING FOR SINGLE AND STACKED FRAMES

• Main Author: KEELER; R. NORRIS
• Format: Patent
• Language: English
• Published: 17.11.1992
• Subjects: ANALOGOUS ARRANGEMENTS USING OTHER WAVES; BASIC ELECTRIC ELEMENTS; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; DEVICES USING STIMULATED EMISSION; ELECTRIC COMMUNICATION TECHNIQUE; ELECTRICITY; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION ORRERADIATION OF RADIO WAVES; MEASURING; PHYSICS; PICTORIAL COMMUNICATION, e.g. TELEVISION; RADIO DIRECTION-FINDING; RADIO NAVIGATION; TESTING

An imaging lidar system is presented which employs a multipulse multiple gating system which is particularly well suited for underwater imaging. The imaging lidar system utilizes a multipulse Q-switched laser operating within the pumping envelope of discharging flash lamps (or other means) to cumulatively illuminate a single frame on a camera (e.g., CCD camera) while the camera is gated repetitively so that each pulse is "observed" at the same depth; that is, the gated camera views that same illuminated area in the ocean. The sequence is repeated at a frequency which is both the laser pulse repetition rate and the camera frame rate. The system also allows the use of multiple cameras with frame addition or with frames processed separately. As a result, energy is extracted from the laser in the form of short (1-10 nsec) pulses by rapidly Q-switching during the time the laser is being pumped by the flashlamps. Provisions are made for subtracting solar noise during daylight, if necessary.