Abstract: The invention relates to an optical system for the detection of a flying or moving object approaching a target, which comprises? (a) one or more transmitter-receiver sets positioned at an external surface of a wall of said target, each of said transmitter-receiver sets comprising: (a.1) a light transmitter for creating a fan-like planar or curved optical curtain in front of said wall of the target; (a.2) a receiver which comprises a two-dimensional focal plane array, said focal plane array being spaced apart from said transmitter and being positioned at a plane not parallel to said optical curtain such that a field of view of said focal plane array covers at least a portion of the entire area of said optical curtain; and (b) one or more processing units for determining at least a location of intrusion of said flying object to within said optical curtain by means of determining pixels within said focal plane array that are affected by reflections or scatter due to said intrusion of said flying object.

Abstract: combined imager and rangefinder includes an imaging sensor and an illuminator. The sensor acquires images of objects in a FOV. The illuminator directs a beam of light via the FOV. In a first mode, the sensor acquires full images of the whole FOV. In a second mode, the sensor acquires partial images, of only part of the FOV, that include a reflection of the light from one of the objects. The range to the object is determined from the location of the reflection in the partial images. Successive range measurements are used to determine whether a collision with the object is imminent.

Abstract: The invention relates to a four-quadrant detector based optical system for detecting and tracking an optical spot, which comprises: (a) a four quadrant detector, which comprises four surfaces that are sensitive to light, said surfaces being separated one from the others by a dead zone surface which is non-sensitive to light radiation; (b) optics between said detector and the scenery, for acquiring an image of a light spot at the scenery, and for impinging the image of the same on said surfaces of the decoder; and (c) a refraction element between said detector and the other optics, which comprises grooves for diverting only the light rays coming from the scenery and directed toward the dead zone, each to a corresponding proximate sensitive to light surfaces of the decoder, while not disturbing the other coming light rays, wherein said refraction element has no physical contact with any of said detector surfaces.