Automatic key identification system

A system for identifying and matching key blanks when duplicating an original key. A key holder is provided which positions the key horizontally along its longitudinal axis with the key's flat sides in a vertical plane. A lensing subsystem lights and forms an image of the front profile of the key. A video camera converts the light image into an electrical signal which is digitized and stored in computer memory. The computer compares the key image with stored images of known key blanks and signals the locksmith by means of an output subsystem the proper key blank to be used in duplicating the key.

BACKGROUND OF THE INVENTION 
This invention relates to duplication of keys, and more particularly to a 
system for identifying key blanks. 
It is well known in the key art that key manufacturers code their key 
blanks in a unique and predetermined manner, each manufacturer having one 
or more code systems distinguished from all other manufacturers. The code 
systems used generally are comprised of a plurality of horizontal grooves 
and indentations of varying shapes, depths and spacing therebetween. 
The most time consuming aspect of duplicating keys involves selection of 
the proper key blank matching the blank from which the original key was 
made. Typically, the locksmith has 50 to 300 various blanks to choose 
from. A mismatched key blank will not fit into the lock for which the 
original key was made even though the vertical notches of the duplicate 
key match the vertical notches of the original key. Not only is the 
process of matching key blanks time consuming, it generally takes from 
three to six months of training for a locksmith to acquire the skills to 
properly match a key blank to an original key within a reasonable amount 
of time. 
There is thus a need for means for quickly and easily identifying the 
proper manufacturer's key blank to be used in duplicating an original key. 
SUMMARY OF THE INVENTION 
It is an object of this invention to reduce locksmith error in selecting 
properly matching key blanks. 
It is a further object of the invention to reduce the amount of locksmith 
training and time necessary to properly match key blanks. 
It is still another object of this invention to provide a system which will 
quickly and accurately identify the proper key blank necessary in 
duplicating an original key. 
It is still further an object of this invention to provide a system for 
automatically identifying the appropriate key blank from an original key 
having horizontal grooves and indentations of a predetermined coded depth 
and spacing. 
These and other objects are preferably accomplished by providing a holding 
device, into which a key is inserted; a lensing subsystem which lights and 
forms an image of the front profile of the key; a video subsystem which 
converts the light image from the lensing subsystem into an electrical 
signal; a digitizer which converts the output of the video subsystem into 
a digital image; a computer subsystem which stores the digital image into 
memory, processes the image and compares it to stored images of known 
keys; and an output subsystem which identifies to the locksmith the proper 
key blank to be used in duplicating the key. 
Other and further objects, as well as various advantages and features of 
novelty which characterize the invention, are pointed out with 
particularity in the claims annexed hereto and forming a part hereof. 
However, for a better understanding of the invention, its advantages, and 
objects obtained by its use, reference should be had to the drawings which 
form a further part hereof, and to the accompanying descriptive matter, in 
which there is illustrated and described a preferred embodiment of the 
invention.

DETAILED DESCRIPTION OF THE INVENTION 
A standard key 1 as shown in FIGS. 2A, 2B and 2C has a head 3 and a shank 
4. For purposes of explanation, the flat sides 9 of the shank 4 are 
positioned vertically and the shank 4 is extended horizontally in 
relationship to the head 3. Along the flat sides 9 of the shank 4 are 
grooves and indentations 5. The grooves and indentations 5 are unique to 
individual manufacturers. The vertical notches 6 along the top 7 of the 
shank 4 and, at times, along the bottom 8 of the shank 4, transform the 
key blank of FIG. 2A into a key 1 uniquely notched for a particular lock. 
The manufacturer's unique coding system of grooves and indentations 5 are 
most easily identified in a head-on view of the front 2 of the shank 4 as 
shown in FIG. 2C. It is this front 2 view which provides the distinctive 
features which allow the present invention to distinguish key blanks among 
manufacturers and among specific manufacturer's product lines. FIGS. 3A 
and 3B, FIGS. 4A and 4B, and FIGS. 5A and 5B provide examples of key 
blanks made by Unican, Ilco #1 and Ilco #2, respectively, and illustrate 
the uniqueness of the head-on views of each. The key 1 used in FIGS. 2A, 
2B and 2C was an American Lock Co. key. The salient characteristics of the 
front 2 view of a key shank 4 is that the cross-sectional profile is 
unique and independent of the vertical notches 6 extending along the top 7 
and/or bottom 8 of the shank 4, thereby allowing a precisely matched key 
blank for use in duplicating a key 1. 
Referring more particularly to the drawings in detail wherein like numerals 
indicate like elements, there is shown in FIG. 1 an automatic key 
identification system comprised of a key holder subsystem 10, a lensing 
subsystem 30, a video subsystem 50, a digitizing subsystem 70, a computer 
subsystem 90, and an output subsystem 110. The key 1 to be duplicated is 
inserted into the key holder 10. The lensing subsystem 30 illuminates the 
front 2 of the key 1 forming a cross-sectional image 35 thereof. The video 
subsystem 50 converts the image 35 into an electrical signal which the 
digitizing subsystem 70 converts into a digital image. The digital image 
is passed to the computer subsystem 90 which stores the digital image into 
its memory 95, processes the digital image and compares it to stored 
digital images of known keys. When a match is made between the image and a 
stored image, the locksmith is told via the output subsystem 110 of the 
proper key blank to be used in duplicating the key 1. 
The key holder subsystem 10 is most clearly shown in FIGS. 6A, 6B, 7A, 7B, 
8, 9 and 10. The purpose of the key holder subsystem 10 is to hold a 
generally bladed object with grooves and indentations along its sides in a 
true horizontal position with the bladed object's flat sides in a 
generally vertical plane, all in relationship to the holder 10. In this 
particular application the key shank 4 is the blade and is inserted front 
2 first into the vertical aperture 11 at the rear 12 of the key holder 10, 
shown in a rear perspective view in FIG. 6A and a real elevational view in 
FIG. 7A. The key 1 is inserted until the shank front 2 meets a viewing 
glass 13 near to the front 14 of the holder 10, shown in a front 
perspective view in FIG. 6B and a front elevational view in FIG. 7B. The 
holder 10 has a housing 15 mounted on a horizontal base 16. Within the 
housing 15 are two vertical and parallel steel dowels 17 in a side-by-side 
relationship perpendicular to the front 14 and rear 12 of the holder 10. 
This may be most clearly understood by viewing the sectional view in FIG. 
8, taken along the line 8--8 in FIG. 7A. An arc section 18 on each 
dowel-to-dowel facing side 22 of a dowel 17 is removed so that each dowel 
17 has a flat portion 22 facing the other dowel 17. Uniformly spaced and 
parallel radial grooves 19 are etched about the center section 20 of each 
dowel 17. A plurality of round, single element springs 21 are positioned 
about each dowel's center section 20 and held within each dowel's radial 
grooves 19. Approximately fifteen to seventeen springs 21 are forced onto 
each dowel's center section 20. FIG. 10 illustrates the result on a single 
dowel 17 and FIG. 9 illustrates the dove-tail effect of the springs 21 
from both dowels 17 across the flat faces 22 of the dowels 17. As may be 
best seen in FIG. 11 the spring elements 21 have a tubular radial 
circumference and are shaped into circles with one opening 23. Small lip 
elements 24 are formed at each opening 23 and aid in the placement of the 
springs 21 about the dowels 17 as well as keeping the springs 21 from 
rotating about the dowels 17 when in position. As may be best seen in FIG. 
8, the housing 15 has vertical apertures 29 along side each dowel 17 for 
placement of the spring lip elements 24 when installing the springs 21 
about each dowel 17. The net effect of this arrangement of springs 21 is 
that the key shank 4 is held in a horizontal alignment with the shank's 
flat sides 9 vertically positioned. The large number of springs 21 on each 
dowel 17 holds the shank sides 9 in and along the grooves and indentations 
5 of the shank 4. 
The key holder 10 orients and locates the front 2 of the key 1 with respect 
to the lensing subsystem 30. The key 1 is inserted through the rear 
aperture 11 of the holder 10, between the spring-encased dowels 17, up to 
the transparent viewing glass 13. Because of the spring 21 and dowel 17 
structure, the key shank 4 is held in a true horizontal position with flat 
sides 9 in a vertical plane. The circular configuration of the springs 21 
across the flat faces 22 of the dowels 17 ensures that only the springs 21 
are in contact with the key shank 4. The design of the holder 10 is such 
that any key 1 in general use may be accomodated. The combined action of 
all of the springs 21 positions, orients and holds the key 1 in a trus 
horizontal position with respect to the holder 10. 
The lensing subsystem 30 is comprised of two or more light bulbs 31, a 
magnification lens 32, F-stop means 33 and a polarizing light filter 34. 
The output of the lensing subsystem 30 is an end-on cross-section image 35 
of the front 2 of the key 1. The key 1 is inserted into the key holder 10 
so that the front 2 of the key 1 touches the viewing glass 13 and is 
halted at a predetermined focal point. The lensing subsystem 30 is mounted 
forward 14 of the key holder 10. The light bulbs 31 are vertically 
juxtaposed on either side of the lens 32. The bulbs 31 illuminate the key 
front 2 at an approximate forty-five degree positive and negative vertical 
to the longitudinal axis of the key shank 4 as illustrated in FIG. 12. The 
light bulbs 31 are small and are powered by any convenient twelve volt 
power source. 
The main source of error in the present invention is from extraneous glare 
and side glints from the key 1. To reduce error non-reflective shields 25 
are positioned on either side of the rear aperture 11. The shields 25 
block out external light from entering the key holder 10 and also act as a 
guide to keep the key 1 properly oriented until engaged by the dowel 
springs 21. Non-reflective shields 25 are also positioned across the 
forward portions of the dowel springs 21, the positioning of which may be 
best understood from FIG. 8. The springs 21 are also painted a 
non-reflective black. The viewing glass 13 is turned slightly on its 
vertical axis to avoid reflecting light back into the lens 32. 
Non-reflective black tape 26 is positioned in vertical strips on either 
side of the viewing glass vertical middle 27 to further reduce the bounce 
back of key glint. The polarizing light filter 34 positioned in front of 
the F-stop means 33 and magnification lens 32 further reduces glint and 
glare. 
The F-stop means 33 illustrated in FIG. 13 provides for different depths of 
field as necessary to fully image the end-on cross-section of the front 2 
of the key 1. Working depth of field is approximately one-half centimeter. 
The magnification lens 32 expands, magnifies and focuses the light image 
35 at a point where it may be easily picked up by the video subsystem 50. 
FIG. 14 depicts an example of what the image 35 might be. It is only the 
cross-sectional edges which are of interest in the identification process. 
As depicted in FIG. 12, the light image 35 is picked up by the input lens 
51 of a conventional video camera which comprises the video subsystem 50. 
In this embodiment an RCA TC1501 video camera was used. The purpose of the 
video subsystem 50 is to convert the light image 35 from the lensing 
subsystem 30 to an electrical signal. This process is well known in the 
art and does not require fuller explanation here. In this particular 
embodiment, the camera 50 has a video output port 52 from which a video 
signal in the 1.0 to 1.4 volt (point to point) amplitude range is 
outputted. Resolution of this subsystem 50 is up to five hundred fifty 
vertical lines. Power is supplied to the video camera 50 from any 
convenient AC source. 
The output from the video output port 52 is then passed to the digitizing 
subsystem 70. The digitizing subsystem 70 is a convention frame grabber 
and in this embodiment a Digital Vision "Computereyes" frame grabber 
module was used. The video output port 52 is connected to the digitizer's 
input connector 71. During every vertical scan period, the subsystem 70 
takes in 192 samples. Thus, one column of 192 pixels, i.e., the smallest 
element of an image that can be individually processed in a video display 
system, is stored every vertical scan. Each vertical scan takes 16.6 
milliseconds. An image is comprised of 320 columns. Therefore, a complete 
image scan requires a little under six seconds. This process is known in 
the art and does not require fuller explanation here. The digitizing 
subsystem's input/output port 72 is connected to the computer subsystem 
90. 
Software running in the computer subsystem 90 controls the acquisition of 
the image 35. The computer subsystem 90 sends a signal to initiate a 
digitizer scan. Following the scan an image is produced in the computer 
subsystem's Random Access Memory (RAM) 91. The image occupies 7,680 bytes 
in RAM 91. FIG. 15A illustrates a bit-mapped video frame matrix in memory. 
Each bit is "1" or "0" depending on whether the pixel is light or dark 
(single level digitization). The digitizer 70 sampled 320 columns of 192 
bits each, which in the computer subsystem 90 is termed 192 lines of 320 
bits each. FIG. 15B illustrates a typical bit-mapped image obtained by the 
digitizing subsystem 70 and stored in RAM 91. The computer subsystem 90 
software scans the image line by line to determine the bit number of the 
left side and the right side of the image object. This operation defines 
the edges of the image object. In order to make the image independent of 
the position of the object in the field of view, the software corrects the 
bit numbers determined above by subtracting the extreme leftmost bit 
number from all bit numbers. The resultant image is illustrated in FIG. 
15C. The image is further translated by correcting the line numbers so 
that the bottom of the image is at the bottom of the frame. FIG. 15D 
illustrates the resultant image. 
The image is then either "saved" or "identified". If it is "saved", it is 
stored both in RAM 91 and disk 92 along with a label chosen by the user. 
If it is "identified", it is compared with "saved" images in RAM 91. The 
actual identification process is as follows. The bit values of the target 
image are subtracted from a saved image line by line. There will be 384 
operations per saved image, i.e., 192 lines.times.2, for left and right 
bit values on each line. The absolute resultant values for the 384 
operations are totalled. This process is repeated for each of the saved 
images. The total closest to zero, within a range preset by the user, is 
the statistical match. The matched saved image is then identified by table 
lookup and the results passed to the output subsystem 110. The general 
capacity of this embodiment of the invention is 300 saved images. However, 
this capacity can be easily expanded. 
The output subsystem 110 can be of many forms. In this particular 
embodiment, the output subsystem 110 is a conventional CRT. Other 
embodiments could include a signal light at each position on a key blank 
storage board, with the matched blank being signalled to the locksmith by 
means of the light at a particular key blank's position. 
It is understood that the above-described embodiment is merely illustrative 
of the application. For example, the entire scanning operation could be 
triggered by a switch in the key holder subsystem 10 as a key 1 is 
inserted into the rear aperture 11. Other embodiments may be readily 
devised by those skilled in the art which will embody the principles of 
the invention, and fall within the spirit and scope thereof.