Arrangement for the optoelectronic recording of large-area fingerprints
First Claim
1. An arrangement for optoelectronic image recording of prints of large-area concave skin parts, particularly whole handprints, comprising:
- an optical support body with a convex support surface for supporting the skin parts with large-area contact with the support surface in order to realize an image recording based on frustrated total internal reflection;
a light source for illuminating the support surface;
a readout beam path for transmitting totally internally reflected illumination light to an image sensor;
said support body having the basic shape of a cylinder around a cylinder axis;
said support body having a cylindrical outer surface with a radian measure and radius which are sufficient to provide at least one freely accessible portion of the outer surface as support surface for the large-area concave skin part;
said support body having a first end face and a second end face, each having a conical recess which is arranged coaxially around the cylinder axis;
said light source extending at least parallel to a surface line of the conical recess and being arranged in the conical recess of the first end face;
said readout beam path including an imaging beam path which is connected to the conical recess of the second end face, which imaging beam path images a strip of the support surface that extends in a line-shaped manner along a lateral line of the outer surface of the support body on said image sensor, which is a linearly extending image sensor, at a total internal reflection angle in an axial plane given by the cylinder axis and the strip; and
said linearly extending image sensor and the imaging beam path being rotatable synchronously around the cylinder axis of the support body in order to record successive line-shaped strips of the frustrated total reflection at the illuminated outer surface due to the skin parts contacting the support surface and to combine them to form a two-dimensional image of the skin part resting thereon.
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Accused Products
Abstract
The invention is directed to an arrangement for the optoelectronic recording of large-area fingerprints, particularly for acquiring prints of the entire palm of the hand. The object of the invention is to find a novel possibility for recording the papillary ridge pattern of a hand which permits a complete optoelectronic image recording with one-time placement of large-area concave skin parts without the use of optical beam paths that are subject to contamination and without having to accept a loss of resolution. This object is met, according to the invention, in that the support body for supporting the skin parts has the basic shape of a cylinder providing a portion of the outer surface with a sufficient radian measure and radius as support surface, the end faces of the support body are each provided with a conical recess which is arranged coaxially around the cylinder axis in order to couple in an illumination beam path and an imaging beam path through the surface lines of the conical recesses, and the imaging beam path and a linearly extending image sensor are rotatable synchronously around the cylinder axis in order to record successive line-shaped strips of the frustrated total reflection at the illuminated outer surface of the support body with the supported skin part.
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Citations
22 Claims
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1. An arrangement for optoelectronic image recording of prints of large-area concave skin parts, particularly whole handprints, comprising:
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an optical support body with a convex support surface for supporting the skin parts with large-area contact with the support surface in order to realize an image recording based on frustrated total internal reflection; a light source for illuminating the support surface; a readout beam path for transmitting totally internally reflected illumination light to an image sensor; said support body having the basic shape of a cylinder around a cylinder axis; said support body having a cylindrical outer surface with a radian measure and radius which are sufficient to provide at least one freely accessible portion of the outer surface as support surface for the large-area concave skin part; said support body having a first end face and a second end face, each having a conical recess which is arranged coaxially around the cylinder axis; said light source extending at least parallel to a surface line of the conical recess and being arranged in the conical recess of the first end face; said readout beam path including an imaging beam path which is connected to the conical recess of the second end face, which imaging beam path images a strip of the support surface that extends in a line-shaped manner along a lateral line of the outer surface of the support body on said image sensor, which is a linearly extending image sensor, at a total internal reflection angle in an axial plane given by the cylinder axis and the strip; and said linearly extending image sensor and the imaging beam path being rotatable synchronously around the cylinder axis of the support body in order to record successive line-shaped strips of the frustrated total reflection at the illuminated outer surface due to the skin parts contacting the support surface and to combine them to form a two-dimensional image of the skin part resting thereon. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification