Shadow image acquisition device

Image analysis – Applications

Reexamination Certificate

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Details

C076S110000, C409S081000

Reexamination Certificate

active

06175638

ABSTRACT:

This invention relates to the field of computer data entry devices, specifically with the purpose of further automatic key identification.
It is common knowledge that key manufacturers code and identify their keys by series of grooves and indentations on lateral surfaces of the key shank. This system of key coding allows for a great number of different key combinations thus, increasing security and reducing chances for identical key combinations. Currently over 10,000 key styles are in use to date. At this time, locksmiths rely on the manual/visual method of key blank identification in order to duplicate the key. This process relies on knowledge, skill and experience of the individual locksmith in order for it to be precise and cost effective. However, the greatest number of errors in key duplication occurs with the incorrect selection of the key blank i.e., choosing one which has groves and indentations which do not match the grooves and indentations of the original key since the differences in the fore-mentioned grooves and indentations are often too minute for correct manual/visual identification. A mistake in selection usually results in repeated duplication using yet another key blank, additional costs acquired due to locksmiths' time, and possibly loss of business. At this time a system for automatic key identification exists (U.S. Pat. No. 4,899,391 William J. Cimino and Robert E. Powers Jun. 24, 1989). Also t known is the key holding system as part of the automatic key identification system (U.S. Pat. No. 5,127,532 William J. Cimino and Robert S Powers Jul. 7, 1992). U.S. Pat. No. 5,127,532 stems from U.S. Pat. No. 4,899,391. U.S. Pat. No. 5,127,532 (Automatic Key Identification System) functions on the following principal. A key is inserted into a mechanical key holder device which positions the key in front of a Lensing/lighting subsystem which shines the light on to the front tip of the key and picks up the resulting visible image- This image is further stored and compared to other images.
Although this particular system is capable of key identification, a variety of inherent flaws make the system inaccurate unreliable and not cost effective. Disadvantages of the system are as follows;
A. Quoted from U.S. Pat. No. 5,127,532 page 4 paragraph 2 “the main source of error is from extraneous glare and side glints from the key.” Glare and side glints result from frontal light projection on to the various facets of the front tip of the key In order to reduce extraneous glare and side glints from the key the inventor positioned a number of non-reflective shields. However, these shields have not significantly reduced the problem.
B. The key holder is designed to accommodate a wide variety of keys and therefore it is not possible to provide a constant precise placement of the key relative to the Lensing/Lighting subsystem. Therefore every time a key is inserted, minute differences in lateral angulation of the key relative to the Lensing/lighting subsystem yield a different image making it difficult or impossible to interpret. Therefor, images taken of the frontal tip are an inaccurate representation of the grooves and indentations of the original.
C. Wear and tear on the front tip of the original key changes the shape of the original. Since this system identifies the key blank based on the visual examination of the front tip incorrect data can be acquired. Quality of the attained image also depends on the key's reflective ability. As an example chrome finish will produce more glare and side glints then a brass finish key of the same design, giving a chrome key larger appearance. To accommodate for this a complex lighting control system had to be implemented increasing cost.
D. Complex mechanical design of the bolder itself raise the price of the unit and increase the chances for mechanical failure. The above mentioned disadvantages are responsible for a low 80% identification rate which is unacceptable by industries standards.
SUMMARY OF THE INVENTION
It is the object of this invention to improve acquisition of the image of the keys' cross-section i.e., the image of the grooves and indentations of the lateral surfaces of the key shank for the purpose of automatic identification of keys. This object can be accomplished by sending light rays along the grooves and indentations from a rear portion of the key shank to the front tip of the key shank. This will project a precise shadow image at the key's cross-section onto the screen where the shadow image will be formed. The advantages of the shadow image vs. previously described image are as follows.
A. The shadow image technique does not produce glare and or side glints because light is not directed at the tip.
B. Difference In lateral angulation of the key will not affect the projection of its grooves and indentations
C. Wear and tear of the front tip of the key will not be a factor since the image is attained from the rear portion of the key shank.
D. The reflective ability of the key is no longer a factor since the image is attained by sending light from the rear portion of the key shank which does not reflect the light as the tip does. There fore the shadow image of the key will be clearly defined on the retaining member. A constant light emitting source will be used for cost effectiveness.
E. Simple design of the holder with only a few moving parts will ensure reliable operation with significantly lower chances for mechanical failure at a significantly lower cost.
Other and further objects, as well as various advantages of this device, are pointed out in greater detail in the claims annexed hereto and forming a part hereof. However, for a better understanding of this device and advantages gained by its use reference should be had to the drawings, which form a further part hereof.


REFERENCES:
patent: 3599147 (1971-08-01), Roders
patent: 3707999 (1973-01-01), Coats
patent: 3955179 (1976-05-01), Planke
patent: 4166949 (1979-09-01), Pöld et al.
patent: 4171161 (1979-10-01), Jung
patent: 4172632 (1979-10-01), Holmes, Jr.
patent: 4625107 (1986-11-01), Planke
patent: 4899391 (1990-02-01), Cimino et al.
patent: 5127532 (1992-07-01), Cimino et al.
patent: 5311286 (1994-05-01), Pike
patent: 5807042 (1998-09-01), Almblad et al.
patent: 5908273 (1999-06-01), Titus et al.

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