Method and apparatus for image capture of information on documents

Method and apparatus for enhancing the image capture of data, such as MICR characters and handwritten and printed information from the face of financial documents having background patterns and illustrations thereon. The documents are back lighted with sufficient illuminating intensity to wash out the less opaque patterns and illustrations so as to enhance the visibility and image capture of the pertinent data.

FIELD OF THE INVENTION 
This invention relates to improvements in document processing, more 
particularly to improved methods and apparatus for the image capture of 
information on a face of the documents, and more particularly to an 
improved method and apparatus for illuminating the documents for increased 
reliability of such image capture. 
BACKGROUND OF THE INVENTION 
Recently, increased efforts have been devoted to improving the efficiency 
of reading written or printed information from the face of paper 
documents. For example, in the area of processing of financial documents 
such as checks, deposit slips, remittance advice stubs, and the like, the 
use of image processing technology has been receiving increased 
application. In accordance with typical image processing techniques, 
documents are transported to a scanning station at which a camera and 
associated electronics are used to capture and digitize all or a portion 
of the image of a face of each of the documents. The digitized image is 
stored and subsequently processed, for example, to display the image (by 
way of a CRT, for instance) to an operator for keying specific information 
into the system processor; the document images also being used, for 
example, for bank statement preparation and/or reproduced for archival 
storage on microfilm, magnetic tape, optical discs, etc. 
A chief advantage of this technology is that the document images, rather 
than the documents, are used for viewing and processing, thus increasing 
the speed and overall flexibility of the document processing operation, as 
well as reducing or eliminating the need for retaining the documents 
themselves. The archiving, cataloging, and other processes which are 
required for record-keeping purposes can be more efficiently carried out, 
and additionally, the space required for such electronically-reproduced 
forms can be much reduced from that heretofore required. 
The increasing use of background illustrations and safety patterns on 
checks and other items, however, poses special problems for the image 
processing of these finanical documents. First, these patterns and 
illustrations increase the amount of data bit storage required in the 
system processor. Secondly, the various scenes of mountains, seashores, 
animals, and the like which are imprinted on the checks oftentimes obscure 
and interfere with pertinent data from being image captured from the face 
of the document, especially the signatures and dollar amounts written 
thereon. In particular, these patterns make it difficult, if not 
impossible, for the camera to discriminate between the important 
information which is to be captured from the face of the check and the 
background illustrations. Amplifying this problem is that conventional 
image processing normally relies upon front lighting of the document and 
such front lighting actually enhances the background patterns, which in 
turn further obscures the information or data which is to be detected or 
captured from the face of the document. 
OBJECTS AND SUMMARY OF THE INVENTION 
In light of the above, it is therefore an initial object of the present 
invention to provide a new and improved method and apparatus in an image 
processing system for reliably detecting and capturing information and 
other data imprinted or hand written on checks and other financial 
documents. 
It is another object of the present invention to provide a new and improved 
method and apparatus for enhancing the ability to image capture data from 
the face of patterned or illustrated checks in a document processing 
system while at the same time minimizing data storage capacity required 
for same. 
It is another object of the invention to provide a method and apparatus of 
the type described in which the undesirable effects of front-document 
lighting are minimized and the reflected light variations due to imprinted 
design patterns are minimized. 
These and other objects, features and advantages will be apparent to those 
skilled in the art from the following detailed description, when read in 
conjunction with the accompanying drawings and appended claims. 
In accordance with a broad aspect of the invention, an apparatus and method 
are provided for uniquely illuminating the financial document so as to 
enhance the electronic detection and image capture of imprinted and 
handwritten information on the face of the document, as distinguished from 
the background illustration or patterns on such document face. The 
illumination approach provides back lighting of the document so that the 
light passes through the document to an electronic detection means, such 
as a document digitizing camera, whereby the imprinted or handwritten 
information is emphasized or enhanced and the lighter, or less opaque, 
background patterns are de-emphasized or eliminated altogether.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Referring now to FIG. 1, the back-lighting apparatus of the invention is 
used in conjunction with known image capture or detection means (not 
shown) which may be, for example, a conventional document digitizing 
camera (and associated electronics) or other type of image scanning 
equipment. One type of suitable image capture apparatus is described in 
U.S. Pat. No. 4,510,619 and assigned to the assignee of the present 
invention. A conventional transport assembly (not depicted) is provided by 
which documents 12 are manually or automatically transported (along a 
transport guide 11) in the direction of the arrow A into the viewing area 
of the image detection means. The most widely used image detection means 
is a digitizing camera in which a small area, such as the illustrated area 
13, is scanned. As the document 12 is transported past the viewing area 
13, a face of the document 12 (or selected portions thereof) are scanned, 
with the captured image stored and used for subsequent processing, as 
desired. For the purpose of this description, and for illustrative 
purposes, the document 12 is a check having background illustrations or 
patterns on the face of the check. 
As illustrated, the check 12 has a number of MICR (Magnetic Ink Character 
Recognition) characters 19, usually along a lower marginal area or field 
20. As is conventional, various lines and block 22 are provided indicating 
locations for entering the identification of the payor and payee, dollar 
amount of the instrument, etc. Of particular concern, patterns or scenic 
designs 23 have been pre-printed on the face of the check and, as shown, 
such designs may extend into the areas or fields in which the MICR 
characters 19 are located or in which the dollar amounts of payor/payee 
identifications have been handwritten or printed. Some of the printed 
characters 19 or handwritten data may in fact be located directly over 
portions of the scenic design 23 so that such design portions practically 
obscure the important check data. 
Two lamps, such as elongated fluorescent tubes 15 and 16, are in 
conventional systems normally provided adjacent to the front face of the 
check 12. The tubes 15 and 16 are typically located side-by-side, on each 
side of the viewing area 13, the detection means (camera) ordinarily 
detecting light reflected from the document 12 (and the data on the face 
of the document) within the viewing area 13. It has been found that 
because of the nature by which light is reflected from the document 12, 
and particularly under the circumstances of this front lighting by itself, 
that the dark areas of the design 23 oftentimes completely obscure the 
information which is desired to be image captured, particularly the 
handwritten information (dollar amount, signature, etc.), and the ability 
of the camera to capture such information. 
To overcome such problem, and in accordance with a preferred embodiment of 
the invention, one or more lamps, for instance fluorescent tubes 17 and 
18, are disposed behind the document 12, as shown in FIG. 1. The lamps 17 
and 18, in the preferred embodiment of FIG. 1, back-light each document 12 
generally in the same area and in the same manner as the tubes 15 and 16, 
only on the back side thereof. The result is that light from the tubes 17 
and 18 travels through the document 12 and tends to "wash out" the less 
opaque or halftone ink that is typically used for printing the scenic 
illustrations and safety patterns on the checks. 
More specifically, the back-lighting approach of the invention takes 
advantage of the fact that the opacity of the medium of which the 
pertinent data that is desired to be image captured (dollar amounts, 
signatures, MICR characters) is printed or written is greater than the 
opacity of the ink used to print the background patterns and 
illustrations. Thus, the light from the tubes 17 and 18 passes through the 
document, and in a diffused manner through the designs and patterns 23, 
and is more effectively blocked by the more opaque handwritten and printed 
data, thus effectively washing out the background illustrations and 
patterns, and enhancing the image capture of the pertinent data. 
Additionally, digitizing camera apparatus which is typically used to 
"capture" the image in many document processing image systems essentially 
operates on the basic principal of detecting and storing transitions 
between light and dark areas on the document; and by utilizing the 
back-lighting technique of the invention, the halftone patterned areas are 
washed out sufficiently so that no light-to-dark transitions appear to 
occur in those areas. Consequently, in addition to enhancing the capture 
of the relevant data from the document, the method and apparatus of the 
invention enables a reduction in the amount of memory that is required to 
accomplish the required storage and processing. 
It should also be noted that in optimizing the image capture of the desired 
relevant data from the document, the data must in the first instance be 
reliably detected; and there is virtually no way to predict in advance the 
type, nature or quality of such data, particularly the handwritten data. 
Accordingly, to achieve such optimization, the back lighting of the 
document is preferably used in conjunction with the front lighting of the 
document, as shown in FIG. 1. 
Furthermore, it has been found that when such combination is employed, it 
may be desirable to adjust the relative intensities of the light emitted 
from the rear tubes 17 and 18 with respect to the front tubes 15 and 16; 
and for this purpose, separate power supplies 25 and 26 are provided to 
independently control the respective intensities of the set of tubes 15 
and 16 and the set of tubes 17 and 18. In addition, it may be desirable to 
use automatic gain type controls for regulating the intensities as a 
function of the amount of light reflected from the document. Because the 
kind, quality and nature of the particular documents being processed may 
vary from one geographical area of the country to the other, or even from 
batch to batch, some experimentation may be necessary to determine the 
desired respective light intensities from the front and rear lights which 
will optimize image capture of the desired data. 
It should be appreciated that although elongated fluorescent tubes 17 and 
18 have been previously described as the back-lighting source, various 
other types of lighting means can be alternatively employed. For example, 
one could use incandescent lamps or, alternatively, light sources which 
emit light of particular wavelength compatible with the spectral 
sensitivity of the particular detection means. 
If only particular areas of the document, rather than the entire document, 
are of interest in particular applications, the light apparatus can be 
arranged to back-illuminate primarily, or only, that particular area of 
interest. For example, as shown in FIG. 2, the rear light arrangement may 
utilize a pair of vertically disposed and shaped light pipes (or other 
similar type light-directing means) 30 and 31 in combination with one or 
more incandescent (or other type) light sources 34 and 35 so as to 
concentrate the light on a particular vertical segment at the back of the 
document 12. 
Alternatively, and as shown in FIG. 3, it may be desirable to 
back-illuminate, for example, only a portion of the lower marginal area 20 
of the document 12 which contain the MICR characters 19; and for this 
purpose, a light pipe 40 having a narrow, shorter vertical height portion 
41 aligned with, and adjacent to, the lower marginal area 20 can be 
employed with a single incandescent lamp 43 used as the light source. 
Although the invention has been described and illustrated with respect to 
particular preferred embodiments, it is understood that such description 
has been made by way of example only and that numerous changes in the 
combination and arrangement of parts can be resorted to by those skilled 
in the art without departing from the spirit and scope of the invention as 
hereinafter claimed.