Method and apparatus for faithful gray scale representation of under water laser images
First Claim
1. An improved under water viewing system for viewing an object at various distances therefrom in water of varying turbidity comprising:
- a light source;
said object being illuminated by said light source;
a receiver for receiving reflected light from said object illuminated by said light source;
light attenuation means; and
control means for selectively varying said light attenuation means for controlling the effective intensity of said reflected light received by said receiver from said illuminated object within said selected dynamic light receiving range regardless of the distance said system is from said object or the degree of turbidity of said water.
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Accused Products
Abstract
In a laser beam X-Y scanning system for use, as for example, in turbid media such as sea water; the laser light reflected from objects is received by an image receiving device or detector such as a photomultiplier tube (PMT). The intensity level of the reflected light is maintained at an intensity level within the dynamic range of the image receiving device by controlling the effective intensity of the laser beam by varying the density of a plurality of series positioned variable neutral density filters positioned between the laser beam generator and the object to be illuminated or the illuminated object and the image receiving device. The light density of each filter is determined by real time environmental conditions and the instantaneous position of the laser light source relative to the object from which the laser light is reflected to the image receiver. The density of each of the plurality of filters is controlled by a computer.
59 Citations
14 Claims
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1. An improved under water viewing system for viewing an object at various distances therefrom in water of varying turbidity comprising:
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a light source; said object being illuminated by said light source; a receiver for receiving reflected light from said object illuminated by said light source; light attenuation means; and control means for selectively varying said light attenuation means for controlling the effective intensity of said reflected light received by said receiver from said illuminated object within said selected dynamic light receiving range regardless of the distance said system is from said object or the degree of turbidity of said water. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. An improved under water viewing system for viewing an object at various distances therefrom in water of varying turbidity comprising:
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a light source; said object being illuminated by said light source; a receiver having a selected dynamic light receiving range for receiving reflected light from the illuminated object; and control means for selectively varying the intensity of said reflected light received by said receiver from said illuminated object within said selected dynamic light receiving range regardless of the distance said system is from said object or the degree of turbidity of said water.
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Specification