Scannerless gain-modulated three-dimensional laser imaging radar

Scannerless laser imaging radar will be the trend of laser imaging radar in future because it has several advantages of high frame rate, wide field of view, small size and high reliability owing to giving up mechanical scanner. A scannerless gain-modulated three-dimensional laser imaging radar is developed: Our system consists of a pulsed laser which is capable of generating 100mJ pulses with a pulse width of 10ns and a center wavelength of 532 nm, and a receiver which is a digital CCD sensor coupled to a GEN II intensifier with a 10nm bandwidth optical filter. The homogenized light beam passes through a diverging lens to flood illuminate the targets. The return light is collected by a Nikon camera lens and amplified by the image intensifier which is electronically driven and can be set to exponentially modulated gain or constant gain. The CCD sensor can record a 12 bit gray-level image with a resolution of 780×582 pixels at a 50 Hz frame rate. For a range image of the target can be extracted by processing an intensity image with exponentially modulated gain and an intensity image with constant gain, the range image is acquired at a 25 Hz frame rate. During our outdoor experiment, the range image of the targets at 500m is acquired with 2m range accuracy and the range image of the targets at about 1 kilometer is acquired with 5m range accuracy in daytime.