METHOD AND DEVICE FOR IMPROVING S/N RATIO OF OBJECT

摘要

PURPOSE: To improve the S/N ratio of an image formed by an object hidden inside or behind a semi-transparent random medium by arranging a focusing device for focusing a light beam sent via the object, a noise filter between the object and the focusing device and a detector to detect the light beam restored by the focusing device. CONSTITUTION: A superhigh speed laser pulse is generated from a laser light source 71 to be admitted into a medium 73 inside which is hidden an object 10. Then, complicate scattered light hits a space limiting noise filter 75 to focus non-scattered and scattered light with an optical fiber 77. At this point, the object 10 moves from one to other points to be scanned and the optical fiber 77 is moved in the direction of the arrow so that a corresponding signal of an image part is focused. A light source 17 and the optical fiber 77 are so arranged to synchronize each other at the positions of irradiation and focusing by a controller 83 monitored by a computer 81 to establish correlation between the irradiated part of the object 10 and the signal focused. The focused signal is guided to a computer 81 through a detector 79.