Abstract:
An apparatus for searching for expressions that appear on a microform medium, the apparatus comprising a microform imager including a sensor for generating digital microform images of one segment of the microform medium at a time, a display screen; and a processor programmed to, while the microform imager is generating a digital microform image: (i) use the digital microform image generated by the microform imager to drive the display screen, (ii) search the digital microform image presented via the display screen for instances of a search expression and (iii) visually distinguish the located search expressions in the digital microform image presented via the display screen.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a computer user interface for a digital microform imaging apparatus and more specifically to a method and apparatus that facilitates word searching on real time microform images and that highlights instances of search words on a display when located. 
     2. Description of the Related Art 
     Microform images are useful in archiving a variety of documents or records by photographically reducing and recording the document in a film format. Examples of typical microform image formats include microfilm/microfiche, aperture cards, jackets, 16 mm or 35 mm film roll film, cartridge film and other micro opaques. For example, a microfiche article is a known form of graphic data presentation wherein a number of pages or images are photographically reproduced on a single “card” of microfiche film (such as a card of 3×5 inches to 4×6 inches, for example). A large number of pages (up to a thousand or so) may be photographically formed in an orthogonal array on a single microfiche card of photographic film. The microfiche film may then be placed in an optical reader and moved over an optical projection path of a film reader until a selected page is in the optical projection path. The reader generates an image of the selected page which is then presented on an imager screen for viewing. Although other electronic, magnetic or optical imaging and storage techniques and media are available, there exists an extensive legacy of film type records storing the likes of newspapers and other print media, business records, government records, genealogical records, and the like. 
     Early microform readers included a projection type system that projected light through the film and on to a screen as well as optics to adjust the magnification of the images generated on the screen. To obtain a copy of an image, at least some of these systems were equipped with printers that would print hard copies of any images required. More recently, digital microform imaging apparatus (DMIA) have been developed that include an imaging sensor as well as optics for focusing film images onto the sensor. The sensor generates a digital bitmap image of the segment of the film in the optical projection path of the reader and provides the bitmap image to a desktop computer. The computer uses the bitmap image to drive a display thereby generating a digital image of the film segment for viewing by a user. The computer can be used to manipulate the bitmap image in many different ways including zooming in and out on the image, rotating the image, changing image contrast, annotating the image, etc. In addition, because the image is in a digital format, the image can be stored for subsequent access in a non-volatile memory. 
     The typical way microform systems are used is that a person that needs to locate information that may be stored on a microform medium identifies one or more microform storage medium (e.g., a microfilm roll) that may include the information being sought and loads the storage medium onto a microform imaging machine. The user then attempts to determine which section of the storage medium may include the information sought and aligns that segment of the storage medium with the optical projection path to generate an image on a display. The user reads/examines the imaged segment or at least a portion thereof in an attempt to find the information sought. More often than not the information sought is not located in the imaged segment and therefore the user moves on to a different segment of the storage medium or to another storage medium without storing or printing out an image of the segment. Once sought information is located in a segment, the user may either print out or store or both print and store the segment image for subsequent access. Thus, in most cases, while a microform imager user may examine a large number of microform segments, the user will only store or print a relatively small number of the segments for subsequent access. 
     In any medium in which most information is expressed in printed words, searching tasks are greatly expedited if word searching can be automated. For instance, in the case of a 1000 page Microsoft Word document where one segment of the document discusses Alexander Hamilton&#39;s relationship with George Washington during the Revolutionary War, for a person unfamiliar with the layout of the document and in need of locating the segment discussing Hamilton, automated word search capability where a computer processor can locate each instance of the name “Alexander Hamilton” in the document is invaluable. In the case of a Word document or the like, the stored document takes the form of a set of ASCII (American Standard Code for Information Interchange) characters, one for each character (i.e., letter, number, space, etc.) in the document. To search for a word, a processor simply compares an ASCII character set representing the word with characters in the document and identifies instances of matches. Thereafter, the processor may highlight the space around each character in a matched word for a user to see via a computer output display screen. 
     In the case of a bitmap image like a PDF (Portable Document Format), one way to search for words in the document is to perform an Optical Character Recognition (OCR) process on the document prior to the word search process to convert the PDF bitmap image into an ASCII type document (hereinafter “an OCR processed document”). After an OCR processed document has been generated and stored, a word search is performed in the usual manner by comparing an ASCII character set that represents a word to be searched with ASCII characters in the document to locate instances of the word. 
     One other way to search for words in a PDF or other bitmap type document is described in U.S. Pat. No. 5,687,253 (Hereinafter the &#39;253 patent”). The &#39;253 patent describes a word search process that is based on word shapes as opposed to the results of a prior OCR process. To this end, the &#39;253 patent describes that a bitmap document image can be processed to generate a word shape for each word in the document and then the word shapes of known words from a dictionary can be compared to the word shapes of the words in the document. 
     While several advantages are associated with word searching capabilities in images that include text, there is no known microform imaging system that facilitates word searching capabilities of any images, much less real time images generated by an imaging system. 
     BRIEF SUMMARY OF THE INVENTION 
     The present disclosure includes a microform imaging system that includes a processor that uses a digital bitmap image from a microform system to drive a display with a real time image and that enables a user to enter a search expression/word, instances of which are to be located and visually distinguished in the real time image. The visually distinguished words help the user to ascertain whether or not a particular image is of interest to the user and, when an image is of interest, the user can either store the image in long term non-volatile memory or can print out a copy of the image. Thus, in at least some cases real time images are searched for words/expressions and there is no need to store the images in non-volatile memory prior to searching. 
     In at least some embodiments the processor performs the word search function without the need to convert text in the image via OCR processes to character strings. This is accomplished in some embodiments by creating a search template for a search expression and using the template to search for word instances. Searching via a word search template as opposed to via an OCR processed document has been found to be faster and in some cases more accurate. Some embodiments of the disclosure include an apparatus for searching for expressions that appear on a microform medium, the apparatus comprising a microform imager including a sensor for generating digital microform images of one segment of the microform medium at a time, a display screen and a processor programmed to, while the microform imager is generating a digital microform image (i) use the digital microform image generated by the microform imager to drive the display screen, (ii) search the digital microform image presented via the display screen for instances of a search expression and (iii) visually distinguish the located search expressions in the digital microform image presented via the display screen. 
     In some cases the segment of the microform imaged by the sensor can be changed and wherein, when the segment of the microform imaged is changed from a first segment to a second segment so that a first digital microform image corresponding to the first segment is replaced by a second digital microform image corresponding to the second segment, the processor eliminating the first digital microform image from memory so that the first digital microform image is not persistently stored for subsequent access. In some embodiments the apparatus further includes a persistent non-volatile memory and an input device whereby a user can indicate via the input device that a displayed digital microform image should be stored in the persistent memory and wherein, prior to an indication that the digital microform image should be stored in the persistent memory, the digital microform image is stored in a non-persistent memory. 
     In some cases the processor stores the digital microform image in random access memory (RAM) as a RAM image and searches the RAM image for instances of the search expression. In some embodiments the apparatus further includes a non-volatile memory in which at least a subset of digital microform images are to be persistently stored, the processor searching for instances of the search expression in digital microform images prior to storing the images in the non-volatile memory. In some cases the processor visually distinguishes by highlighting instances of the search expression in the digital microform image presented on the display screen. In some embodiments the apparatus further includes an input device useable to specify the search expression, the processor searching by searching for the search expression entered via the input device. In some cases the input device includes a search input field presented via the display screen in which an apparatus user enters the search expression. In some cases the microfilm medium segment used to generate the digital microfilm image can be changed by a user and wherein, when the microfilm medium segment used to generate the digital image is changed, the digital microform image presented via the display is changed and the search input field is persistently presented via the display screen so that the user can cause the processor to search for the search expression in the changed digital microform image. 
     In some cases the search expression includes a word. In some cases the processor searches for search expression instances without performing OCR on the digital microform image. In some cases the processor searches for instances of the search expression by first creating an expression template representing the shape of the search expression and then searching the digital microform image for instances of the expression template. In some cases the processor searches for instances of the expression template by selecting a portion of the expression template as an initial template, searching the digital microform image for instances of the initial template to identify expression candidates and then searching areas around each expression candidate within the digital microform image for an instance of the search expression using the expression template. 
     Other embodiments include an apparatus for searching for expressions that appear on a microform medium, the apparatus comprising a microform imager including a sensor for generating a digital microform image of one segment of the microform medium at a time wherein the imager includes controls for changing the segment of the microform medium that is used to generate the digital image, a display screen for displaying the digital microform image, a non-volatile memory and a processor programmed to receive the digital microform image generated by the imager and, prior to persistently storing the digital microform image in the non-volatile memory (i) search for instances of a search expression in the digital microform image and (ii) when at least one instance of the search expression is located within the digital microform image, visually distinguish the at least one instance of the search expression on the display screen. 
     Some embodiments include a method for searching for expressions that appear on a microform medium, the method comprising the steps of using a microform imager including a sensor to generate digital microform images of one segment of the microform medium at a time, while the microform imager is generating a digital microform image (i) using the digital microform image generated by the microform imager to drive a display screen, (ii) searching the digital microform image presented via the display screen for instances of a search expression and (iii) visually distinguishing the located search expressions in the digital microform image presented via the display screen. 
     In some cases the segment of the microform imaged by the sensor can be changed and wherein, when the segment of the microform imaged is changed from a first segment to a second segment so that a first digital microform image corresponding to the first segment is replaced by a second digital microform image corresponding to the second segment, eliminating the first digital microform image from memory so that the first digital microform image is not persistently stored for subsequent access. 
     In some cases the method is for use with a persistent non-volatile memory and an input device, the method further including the steps of receiving an indication via the input device that a displayed digital microform image should be stored in the persistent memory and wherein, prior to the indication that the digital microform image should be stored in the persistent memory, storing the digital microform image in a non-persistent memory. In some cases the method further includes the step of storing the digital microform image in random access memory (RAM) as a RAM image and searching the RAM image for instances of the search expression. In some cases the method is for use with a non-volatile memory in which at least a subset of digital microform images are to be persistently stored, the method further including the step of searching for instances of the search expression in digital microform images prior to storing the images in the non-volatile memory. In some cases the step of visually distinguishing includes highlighting instances of the search expression in the digital microform image presented on the display screen. 
     In some cases the method is for use with an input device useable to specify the search expression, the method including searching for search expression entered via the input device. In some cases the input device includes a search input field presented via the display screen in which an apparatus user enters the search expression. In some cases the microfilm medium segment used to generate the digital microfilm image can be changed by a user and wherein, when the microfilm medium segment used to generate the digital image is changed, the digital microform image presented via the display is changed and the search input field is persistently presented via the display screen so that the user can cause searching for the search expression in the changed digital microform image. In some cases the search expression includes a word. 
     In some cases the step of searching for search expression instances includes searching without performing OCR on the digital microform image. In some cases the step of searching for instances of the search expression includes first creating an expression template representing the shape of the search expression and then searching the digital microform image for instances of the expression template. In some cases the step of searching for instances of the expression template includes selecting a portion of the expression template as an initial template, searching the digital microform image for instances of the initial template to identify expression candidates and then searching areas around each expression candidate within the digital microform image for an instance of the search expression using the expression template. 
     Yet other embodiments include a method for searching for expressions that appear on a microform medium, the method comprising the steps of using a sensor to generate a digital microform image of one segment of the microform medium at a time wherein the imager includes controls for changing the segment of the microform medium that is used to generate the digital image and using a processor to receive the digital microform image generated by the imager and, prior to persistently storing the digital microform image in a non-volatile memory (i) searching for instances of a search expression in the digital microform image and (ii) when at least one instance of the search expression is located within the digital microform image, visually distinguish the at least one instance of the search expression on the display screen. 
     These and other objects, advantages and aspects of the invention will become apparent from the following description. In the description, reference is made to the accompanying drawings which form a part hereof, and in which there is shown a preferred embodiment of the invention. Such embodiment does not necessarily represent the full scope of the invention and reference is made therefore, to the claims herein for interpreting the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         FIG. 1  is a perspective view a DMIA and associated computer that are consistent with at least some aspects of the present invention; 
         FIG. 2  is a schematic illustrating various components of the DMIA and computer shown in  FIG. 1  in greater detail; 
         FIG. 3  is a perspective view of the DMIA shown in  FIG. 1 ; 
         FIG. 4  is a schematic illustrating a screenshot of the user interface shown in  FIG. 1 ; 
         FIG. 5  is a similar to  FIG. 4 , albeit showing a screenshot where a displayed microform image shown in  FIG. 4  has been enlarged; 
         FIG. 6  is a schematic illustrating a search template that is consistent with at least some aspects of the present invention; 
         FIG. 7  is a schematic illustrating a portion of the template shown in  FIG. 6  that is used during a first phase of a search process in at least some embodiments of the present invention; 
         FIG. 8  is a schematic illustrating a line search pattern over microform image text that is consistent with at least some embodiments of the present invention; 
         FIG. 9  is a schematic illustrating exemplary match scores for a possible template to search expression match that is consistent with at least some embodiments of the present invention; 
         FIG. 10  is a flow chart illustrating a search process that is consistent with at least some aspects of the present invention; and 
         FIG. 11  is sub-process that may be substituted for a portion of the process shown in  FIG. 10 , to search for instances of a search expression in an iterative fashion. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring now to the drawings wherein like reference numerals correspond to similar elements throughout the several views and, more specifically to  FIG. 1 , there is shown a digital microform imaging system  20  which generally includes a digital microform imaging apparatus (DMIA)  22  connected to a computer  24 . Referring also to  FIG. 2 , computer  24  includes one or more displays  26 , one or more user input devices such as a keyboard  28  and/or a mouse  30 , a processor  31 , a temporary memory  33  (i.e., a random access memory (RAM)) and a non-volatile memory  35 . DMIA  22  and computer  24  can be placed on a worksurface  32  of a desk or the like for convenient access and ease of use. DMIA  22  is connected for communication (e.g. via Firewire IEEE 1394) to computer  24  via cable  34 . Although cable  34  is described as an electrical type cable, alternatively DMIA  22  and computer  24  can communicate via fiber optics, wirelessly through infrared or radio frequencies, etc. Other details of computer  24  and the general computing environment are discussed in more detail below. 
     DMIA  22  is described in U.S. patent application Ser. No. 11/748,692, titled “DIGITAL MICROFORM IMAGING APPARATUS”, filed May 15, 2007, which application is incorporated by reference. Referring more particularly to  FIGS. 2 and 3 , DMIA  22  includes an approximately monochromatic illumination source  36 , such as a light emitting diode (LED) array which transmits incident light  38  through a diffuse window  40  along a first optical axis  42  of apparatus  22 . Light emitting diode (LED) array  36  can be an approximately 13×9 array of individual LEDs operating in the 495-505 nm wavelength region, although array  36  is not limited to such parameters. The relatively monochromatic nature of source  36  helps reduce chromatic aberration in DMIA  22 , thereby improving the optical resolution of the images produced. Diffuse window  40  can be a frosted glass which diffuses the light emanating from array  36 , thereby creating a more uniform illumination source. 
     A microform media support  44  is configured to support a microform media  46  within the path of light  38  and along first optical axis  42 . In the embodiment shown support  44  is an X-Y table which is movable in a plane which is approximately orthogonal to first optical axis  42 . Microform media support  44  includes a frame which supports a first window  50  on one side of media  46  and a second window  52  on the other side of media  46 . Although not shown, second window  52  hinges upward when the frame is moved forward and similarly hinges downward when the frame is moved rearward. In this way the microform media  46 , can be placed and held securely between windows  50 ,  52  for viewing. 
     An approximately 45° fold mirror  70  ( FIG. 2 ) reflects the incident light transmitted through microform media  46  approximately 90° along a second optical axis  72 . First optical axis  42  and second optical axis  72  can be thought of as segments of the single or main optical axis. Fold mirror  70  advantageously shortens the overall longitudinal length of the optical axis which allows DMIA  22  to be more compact. 
     An imaging subsystem includes a lens  90  that includes an adjustable aperture. Lens  90  may have a fixed focal length of 50 mm, for example, which has the advantage of a relatively large depth of focus. An area sensor  92  includes an area array CCD sensor with a two dimensional array of sensor elements or pixels, for example, with a 3.5 μm2 pixel size, or other types of sensors and pixel sizes depending on resolution size requirements. The area array nature of sensor  92 , when compared to a line sensor, eliminates the need for scanning of the sensor when viewing two dimensional images. A light baffle  126  can be connected to area sensor  92  to reduce stray light incident on sensor  97  and thereby further improve the resolution and signal to noise of DMIA  22 . Light baffle  126  can have an antireflective coating at the front and inside surfaces of the baffle to further reduce stray light incident on sensor  92 . Algorithms for moving the lens and sensor to appropriate respective locations to achieve proper magnification and focus of an image allows DMIA  22  to autofocus without the need for iterative measurements and refocusing of the lens  90  during magnification changes to accommodate different reduction ratios of different film media. 
     A controller  116  is electrically connected to motors associated with lens  90  and area sensor  92  where the controller  116  is for receiving commands and other inputs from computer  24  or other input devices, controlling the motors and other elements of DMIA  22 , and for outputting a digital microform image corresponding to area sensor  92 . To this end, controller  116  includes one or more circuit boards which have a microprocessor, field programmable gate array, application specific integrated circuit or other programmable devices; motor controls; a receiver; a transmitter; connectors; wire interconnections including ribbon wire and wiring harnesses; a power supply; and other electrical components. Controller  116  also provides electrical energy and lighting controls for LED array  36 . The motors can be DC servomotors, or other motors. 
     The present invention is not limited by the DMIA  22  shown as there are other DMIAs, or microfilm or micro opaque readers, scanners, etc., which are available which can be used in conjunction with a computer and the CUI of the present invention. Further, the present invention is not limited by a separate DMIA  22  and computer  24 . For example, computer  24  can be integrated into DMIA  22 , or can be part of controller  116 . Yet further, monitor  26  can be a part of DMIA  22  instead of a separate device. 
     Media  46  can include any microform image formats such as microfilm/microfiche, aperture cards, jackets, 16 mm or 35 mm film roll film, cartridge film and other micro opaques. Micro opaques are different than transparent film. Images are recorded on an opaque medium. To view these micro images one needs to use reflected light. The present invention can use LED arrays (not shown) for use with micro opaques, which can be the same, or similar to, the monochromatic LED&#39;s that are used in illumination source  36 . In the embodiment of  FIG. 3 , DMIA  22  includes a microform media support in the form of motorized roll film attachment with supply side  62  and take up side  64  and film guides  66  and  68 , in addition to an X-Y table  44 . 
     Referring now to  FIGS. 1 and 4 , computer  24  includes a software computer user interface (CUI)  100  displayed by monitor  26  with user inputs to control DMIA  22  in general. CUI  100  can be in the form of at least one instruction executed by processor  31 , where the instructions of 100 are stored on a computer-readable storage medium. CUI  100  generally includes a display area  104  and a toolbar  102  with user selectable controls. The user selectable controls presented via toolbar  159  include, among others, an image zoom control repeated by icon  114 , a save control represented by icon  112  and a word search control represented by search icon  120 . The toolbar controls  159  can be selected by a user moving a mouse controlled cursor  122  (see  FIG. 4 ) on to one of the icons and a left clicking mouse  30 . A film control tool  110  is also presented via CUI  100  that can be used by a system user to advance or back up a roll of film supported by DMIA  22 . 
     Referring still to  FIG. 4 , and also again to  FIGS. 1 through 3 , when a DMIA user places a microform segment within the path of light  38 , sensor  92  generates a digital microform image which is provided via cable  34  to processor  31 . Processor  31  uses the digital microform image to directly drive display  26 . Thus, as the microform image is altered, the image presented via display  26  is immediately altered as well so that the image obtained by sensor  92  is always used to drive display  26  essentially in real time. Here, the bitmap image that is displayed is not stored in non-volatile memory  35  until the system user selects save icon  112 . By not storing the real time images, the process of scanning the microform segments and presenting the segments via display  26  is expedited and the overall process is more appealing to the end user as scanning and image presentation appears to be and actually is more fluid. 
     In  FIG. 4 , an exemplary image of a front page of a newspaper is shown in display area  104 . The image includes pictures and text which comprise various articles. The icons in toolbar area  102  can be selected to modify the appearance of the microform image area  104 . For example, a segment or portion of the image in area  104  is shown in an enlarged or zoomed format in  FIG. 5 . Here, the image in area  104  is a digital bit map image and, in at least some embodiments, the image is never processed via an optical character recognition (OCR) process. 
     Referring still to  FIGS. 4 and 5 , one particularly advantageous function that is associated with the present disclosure allows a system user to cause processor  31  (see also  FIG. 2 ) to search an image presented within area  104  for specific words or phrases that may be of interest to the system user. For example, where a system user is looking for articles related to a House of Representatives within a state, the user may want to search for any instances of the term “House” in stories within a newspaper that is stored on a microform storage medium. With an image to be searched presented in area  104 , referring to  FIG. 4 , a system user can select search icon  120  via cursor  122 . When icon  120  is selected, in at least some embodiments of the present disclosure, a separate “find text” window  108  is opened. Window  108  includes a title bar  130 , a “window close” icon  132 , a search expression field  134  and a “find” icon  136 . Title bar  130  can be used to move window  108  to different locations within CUI  100 . Window close icon  132  can be selected to close the find text window  108 . Expression field  134  is provide to allow the user to enter text or a phrase to be searched for within the presented image. Here, text is entered by selecting field  134  and then using keyboard  28  (see again  FIG. 1 ). Once a search expression is entered within field  134 , the user can select find icon  136  to submit the search expression to processor  31  for searching purposes. 
     Referring still to  FIG. 4  and now also to  FIG. 5  where a portion of the image in  FIG. 4  has been enlarged, it can be seen that in the present example, after the term “house” has been entered in field  134  and find icon  136  has been selected, the processor  31  locates four separate instances of the search expression “house,” where the separate instances are labeled  150   a ,  150   b ,  150   c  and  150   d . In the illustrated embodiment, each instance of the search expression identified within a presented image is visually distinguished in some fashion. For instance in  FIGS. 4 and 5 , each instance  150   a  through  150   d  is visually distinguished by placing a rectangle around the instance. Other ways of visually distinguishing include highlighting each instance, placing a blinking box around each instance, placing an arrow adjacent each instance, etc. 
     Importantly, the expression or work search method in at least some embodiments of the present invention is preformed without the need for OCR processing and instead is performed directly on the bit map image presented within area  104 . To this end, in at least some embodiments, after a search expression has been received by processor  31 , the processor creates a template of the search word or expression and then performs an iterative search of the displayed image to find instances of the expression. More specifically, in at least some embodiments, referring to  FIG. 6 , to create a search expression template, after a search expression has been received, processor  31  lays a multi-column and row raster over the search expression and then, for each element in the raster, generates an element value that indicates a percentage of the element covered by the search expression. In  FIG. 6 , raster elements are generally identified by numeral  182  where an “H” from the search expression “house” is shown covering a portion of the raster where raster elements that are overlapped by the search expression are shown in cross-hatch. Exemplary elements overlapped by the letter H are collectively identified by numeral  186 . The combination of numbers representing the percentages of elements overlapped by the search expression comprise the template  180  in the present example. Other template types are contemplated where weights may be applied to element values based on empirical data related to modifications that tend to increase accuracy of search results. In addition, more complex templates are contemplated, the illustrated template having been simplified in the interest of simplifying this explanation. 
     After the search expression template has been generated, in at least some embodiments, processor  31  selects a portion of the template to be used during a first rough phase of the image searching process designed to quickly identify word/expression match candidates. Referring to  FIG. 7 , in at least some embodiments, the template portion used for the first phase of the search includes a generally central line pattern  190  through the template elements where each element in the selected portion includes a number indicating the percentage of the element overlapped by the search expression. Hereinafter, the portion  190  is described as a center pattern. While a center pattern is used in the present example during the first phase of searching, it should be appreciated that other patterns derived from the template may be employed and the invention should not be limited to use of a center pattern during the first rough search phase. 
     After the center pattern  190  has been identified, referring to  FIG. 8 , the processor  31  searches along a series of horizontal lines through the image presented in area  104  (see again  FIG. 5 ) for possible matches between the center pattern and data within the digital bit map microform image. Exemplary search lines are collectively labeled  200  in  FIG. 8 . While only a small number of search lines are shown in  FIG. 8 , it should be appreciated that a large number of search lines are used during normal operation so that any and all instances of the center pattern are detected and associated with at least one of the search lines. An exact match between the center pattern and a portion of a search line is not required to identify a possible instance of the search expression and instead, some error is tolerated as a second search phase is used to eliminate erroneous instances of identified search expressions. In  FIG. 8 , exemplary lines  200   a ,  200   b ,  200   c  and  200   d  correspond to separate possible instances of the search expression house. 
     Once possible instances of the search expression have been located, processor  91  uses the entire search template  180  to search the area around each possible instance to more accurately identify and verify instances of the search expression that have been identified. To this end, referring to  FIG. 9 , for each element  222  in the search template, in at least some embodiments, match scores are provided that indicate how closely a possible search expression instance matches the template. In  FIG. 9 , match scores are provided for each template element (see cross-hatched elements) that is at least partially overlapped by the search expression (see “H” and portion of “O” in  FIG. 9 ) where a relatively higher match score indicates a better correlation between a template element and a match candidate element. Where the combination of matched scores corresponds to a value that is greater that a match threshold, a template to expression match is determined to have occurred and processor  31  then highlights or otherwise visually distinguishes the instance within area  104  (see again  FIG. 5 ). 
     Referring now to  FIG. 10 , an exemplary method  158  that is consistent with at least some aspects of the present invention is illustrated. Referring also to  FIGS. 1 and 2 , at process block  160 , a user places a microform segment in the viewing area of DMIA  22  and at block  92 , sensor  116  generates a digital bit map microform image which is provided to processor  31 . At block  164 , processor  31  uses the microform image to drive display  26  in real time. 
     Referring still to  FIGS. 1 ,  2  and  10 , at decision block  166 , processor  31  determines whether or not a system user has indicated that the presented image should be stored in the non-volatile memory  35 . Where the user indicates that the image should be stored in non-volatile memory  35 , control passes to block  168  where the image is stored for subsequent access. At block  166 , if the user does not indicate that the image should be stored, control passes to block  170  where processor  31  determines whether or not the user has indicated a desire to search for a word or phase within the image presented. If the user has not indicated a desire to search, control passes back up to block  162  where the microform segment continues to be imaged. 
     Once again, referring to  FIG. 4 , a user indicates a desire to search by selecting icon  120 . Once icon  120  is selected, control passes to block  172  where processor  31  presents the find text window  108  shown in  FIG. 4 . At block  174 , a user enters a search expression or word to be searched in field  134  and then selects find icon  136 . 
     Referring still to  FIGS. 1 ,  2  and  10 , after find icon  136  is selected (see again  FIG. 4 ), processor  31  searches the displayed bit map image in real time for the search expression (i.e., for the entered word). At decision block  178 , where one or more instances of the word are located, control passes to block  182  where processor  31  highlights the instance or multiple instances of the word/search expression in the bit map image. Where an instance of the search expression has been identified at block  178 , control passes to block  180  where processor  31  indicates that no match has occurred in some fashion. After blocks  180  and  182 , control passes back up to block  162  where the process continues as above. If a user switches the segment of the microform storage medium that is being imaged via DMIA  22 , process  158  is repeated for the new segment. In at least some embodiments, when a user performs a word search of one segment and then switches to view another microform segment, the find text box  108  (see again  FIG. 4 ) remains on the CUI with the previously sought search expression in field  134  so that the user can simply reselect find icon  136  to continue the search process using the same search expression. 
     Referring now to  FIG. 11 , a sub-process  240  that maybe substituted for a portion of the process shown in  FIG. 10  is illustrated. Referring also to  FIG. 10 , after a search word or expression has been received by processor  31  at block  174 , control may pass to block  242  in  FIG. 11  where processor  31  creates a template as shown best in  FIG. 6 . Next, at block  244 , processor  31  uses the center pattern  190  (see again  FIG. 7 ) from the template to line search (see again  FIG. 8 ) throughout the displayed microform image for possible instances of the search expression. At decision block  246 , where no potential matches have occurred, control passes to block  248 . At decision block  248 , where the entire displayed image has been examined, control passes back to block  180  in  FIG. 10  where processor  31  indicates that no match has occurred. At block  248 , where the entire displayed image has not been examined, control passes back up to block  244  where processor  31  continues the line searching process. 
     Referring still to  FIG. 11 , at decision block  246 , where a potential match has been identified, control passes to block  252  where processor  31  compares the entire search template to an area proximate the potential match. At block  254 , where a search expression match has been verified, control passes back to block  182  in  FIG. 10  where the instance or instances of the search expression in the bit map are highlighted. 
     The foregoing description was primarily directed to a preferred embodiment of the invention. Although some attention was given to various alternatives within the scope of the invention, it is anticipated that one skilled in the art will likely realize additional alternatives that are now apparent from disclosure of embodiments of the invention. Accordingly, the scope of the invention should be determined from the following claims and not limited by the above disclosure.