Crisp, Robert, Jr.

Wells, Barry C.

ScholarWorks@UARK

Journal of the Arkansas Academy of ScienceVolume 44 Article 321990Image Enhancement of Faded Historic DocumentsRobert Crisp Jr.University of Arkansas, FayettevilleBarry C. WellsUniversity of Arkansas, FayettevilleFollow this and additional works at: http://scholarworks.uark.edu/jaasPart of the Archival Science CommonsThis article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able toread, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking priorpermission from the publisher or the author.This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the ArkansasAcademy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact ccmiddle@uark.edu, drowens@uark.edu,scholar@uark.edu.Recommended CitationCrisp, Robert Jr. and Wells, Barry C. (1990) "Image Enhancement of Faded Historic Documents," Journal of the Arkansas Academy ofScience: Vol. 44 , Article 32.Available at: http://scholarworks.uark.edu/jaas/vol44/iss1/32Proceedings Arkansas Academy of Science, Vol. 44, 1990 121GENERAL NOTESIMAGEENHANCEMENT OF FADED HISTORIC DOCUMENTSThe need to preserve historic documents is generally recognized and few would deny that these documents become more valuable with thepassage of time. Unfortunately, as time passes, the document becomes faded and/or tattered making it less and less legible. Methods are availableto increase the lifeof the original, but these often inhibit access. Facsimiles are often used to circumvent this problem. But many facsimiles pro-cedures have limitations; for example, a first generation copy is better than a second generation copy and successive copies lose information. Digital(or computerized) copies overcome many of the obstacles encountered with the present methods of preservation."Digitalcomputer image enhancement has proven highly useful in numerous fields. Remote sensing, astronomy, and medical diagnosticsin particular have experienced quantum leaps in performance through the introduction of this technology". (Asmus, John F., "Digital Image Pro-cessing in ArtConversion", BYTE, March 1987, p. 151). With a digital copy, the document can be viewed as having an extremely fine grid ofpoints. These points or dots (often called pixels) can be turned on or off in a simple "line art" copy, or they may have different intensities, orgray scales, to provide a copy ofblack and white photographs. Finally, they may have both intensity and color to provide a fullcolor copy. Thesecomputer generated copies have several advantages: 1) they do not exhibit degradation over time other than the risk (which can be minimized)of losing the copy or corrupting the data; 2) a tenth generation copy is as good as a first generation copy; 3) they can be easily exchanged by usingelectronic media or electronic transmission; and 4) most importantly, they lend themselves tocomputer indexing and retrieval so they may be retrievedin milliseconds and viewed on video screens.Traditional methods of image enhancement involve "gray scale reversal, stretching of gray levels, modification of the histogram to the desiredfunction, and so on". (Chellappa, Rama and Alexander A. Sawchuck, DigitalImage Processing and Analysis, Vol. 1, 1985, p. 426). Several areasof enhancement have emerged. These consist of optical character recognition, satellite imaging and medical photography, to name a few. As mostof these areas are unrelated, what is available today is a collection of algorithms and functions which may or may not apply to a given image.Aprimary obstacle of digital copies has been the very large amount of data (and associated cost) required for a copy. Several developmentshave occurred which lessen this problem: 1) computers are much faster and the speed is doubling about every 2 years; 2) the cost of storing digitaldata is dropping by half every 2 years. The development of data compression algorithms also significantly reduce the data storage requirements.Taken together, digital archives are a viable alternative today, and a near certainty for the future.This paper explores the unique problems associated with digitizing old documents that contain handwritten script. Additionally, a methodis suggested for accurately capturing the image data.This project consists of an interdisciplinary approach to providing an alternate method of document preservation. Several branches of thehumanities, coordinated with computer science and engineering at the University of Arkansas in Fayetteville willbe involved.The proposed project task force is centered around a newly formed History Technology Laboratory at the University ofArkansas. This groupconsists of a board which contains representation from engineering and the humanities. The humanities reprsentatives make up a majority of thegroup. History, library science and literature represent some disciplines within the humanities in this group.Many books and documents address the topic of image processing. Most of the existing image processing systems are expensive and difficultto access and use; however, many ofthe techniques and algorithms used in existing systems and described in current books can be utilized in this project.The National Archives and the Library of Congress are developing a similar type of imaging system. Recent contacts withpersonnel at theLibrary of Congress indicate that there are some complexities in their system. These larger systems typically are few in number and complicatedto use. One of the goals of this project willbe to produce a prototype which willbe cost effective and easy to use. The prototype should havethe capability of recovering difficult to read text and producing a facsimile which would be representative of the original document.This work was performed on a 386 based machine with a high resoluton (1,024 X 768) monitor. The output is from a 300 DPIHP LaserJet.Higher output densities are available but are not yet implemented. Alternate storage devices (tape, optical disk, etc.) are being evaluated and effortsare underway to find or create an image database front end.A typical old document contains nothing other than freehand script. Typically, the quality of the paper and the legibility of the text varythroughout the entire length and width of the document. Thus, some parts of the page willbe clearly legible while other parts may be totally illegi-ble. Refer to Fig. 1. "Abasic tool utilized in performing subjective enhancement and image analysis is the image histogram. The histogram revealsthe distribution of digitized intensity within an image....". (Green, William B., DigitalImage Processing, A Systems Approach, 2nd ed., p. 64).Since each document has such variations as described above, difficultyoften exists when applying a single algorithm to the entire histogram. Anyenhancement scheme which applies to the entire document must take this into account.Existing systems are rarely applicable in this situation. Optical character recognition, satellite and medical imaging contribute concepts andgeneral guides to script enhancement but do not provide a total solution. Algorithms which affect the entire page can be utilized to improve thequality of a document to some degree. The algorithms utilized on the letter in Fig. 1 were (in order): 1) adjusted brightness, 2) adjusted contrast,3) performed linear equalization and 4) sharpened the image. The algorithms produced Fig. 2. Notice that there are 2 horizontal areas splittingthe document into thirds. These are folds in the paper. To make matters worse, at some time in the past scotch tape was applied to approximatelytwo-thirds of these areas starting at the left edge. Figure 3 displays a blowup of part of the lower band. (The vertical and horizontal measurementswere altered automatically by the software in an attempt to fit the picture on a single page.) Figures 4 and 5 represents a best attempt to clarifythe words underneath the scotch tape. The letters barely become readable in Fig. 6.The intent is to create a proximity algorithm to locate and enhance line segments. Figure 7 shows the desired end result. Lines will typicallyhave characteristics which distinguish them from other marks. Lines willnormally be ofa consistent gray level in a continuous fashion and furtherwillnot be "very wide". These features will allow the algorithm to discern the difference between the background and the line.The first 75 (V* inches at 300 DPI) rows of pixels are read into the computer memory from the image file. The entire document cannot beread at once due to hardware and software requirements. The algorithm must then perform 2 functions. The first executes the necessary stepsrequired to locate a line segment. The second "traces" the line segment and records the locations of those pixels which are recognized as partof a line into a table. The remaining pixels are then turned to white. The information is written back out to disk after performing these 2 steps.The script may then be enhanced through the use of readily available software by adjusting brightness and contrast levels.Script detection on older manuscripts has been discussed with relationship to existing enhancement systems. Inolder manuscripts, existingalgorithms proved inadequate. The need for new algorithms led to the formation ofan History /Technology Laboratory. The purpose of the laboratoryin regards to this project was to establish algorithms which are specific to script detection. Investigation of present technology led to the develop-ment of a proximity algorithm which locates and "traces" a line segment. This paper also included an example of an enhanced document.ROBERT M. CRISP, JR., Computer Science Engineering Department, Engineering 313, University ofArkansas, Fayetteville, AR 72701 and BARRYC. WELLS, Acxiom, Inc., GENESIS Program, University of Arkansas, ERC 214, Fayetteville, AR 72701.21Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32Published by Arkansas Academy of Science, 1990122Proceedings Arkansas Academy of Science, Vol. 44, 1990Arkansas Academy of ScienceJ§|§j| ' A--vt-(~£~ -''-iJll- ''" "' c""1 L-''''¦''''' -y ¦""'V-r-C.._ //';„/ /<':'*-'¦-' /// /'; »'?' ;'''' / «' i'tri Lt-''./—'.'-.>¦¦',¦' ¦ . "'y' t/1*1 !rr f .¦ h"..(*¦ 0 f'T'-,-Kf .iff • '¦ ¦>>^- \; «Figure 1. Original document produced in 1900 Figure 2. Original document after adjusting brightness and contrast,applying linear equalization and sharpening the image.9H9HI HBHHHHHH HIKK9MI wwutou-X. 'us." 1 JLM'* ¦ • ¦ ' 'K» MiriBHUMBMiJem iBiiHH^u£I2LW:iITinililffflill^^ 'it/ /'i7 r i // /Nfr / / / .# ' .Figure 3. Small section of original document Figure 4. Figure 3 after applying threshold filter122Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32http://scholarworks.uark.edu/jaas/vol44/iss1/32Proceedings Arkansas Academy of Science, Vol. 44, 1990 123General NotesFigure 5. Figure 4 after applying equalization and sharpnessFigure 7. Desired end result after applying proximity algorithmFigure 6. Figure 5 after applying contrast and brightnessTHE IMPACT OF MICROPROCESSOR PROTECTED MODE PROGRAMMINGON UNDERGRADUATE EDUCATION INENGINEERING TECHNOLOGYThe purpose of this paper is to examine some of the rapid changes that have recently occurred (and are continuing to occur) in microcom-puters and the impact of these changes on both faculty and students in engineering, technology, and related fields — such as physics, biology,mathematics, and chemistry.A microcomputer is any computer that uses a microprocessor for its central-processing-unit (CPU). In fact, a "microprocessor" can be describedor defined as a CPU on one integrated circuit or "chip." Because of their small size and low cost, microprocessors, which were first developedin 1971, have revolutionized the computer industry. Before the advent of microprocessors, all computers were generally classified as main-frameor minicomputers. Since main-frame and mini computers are usually very large and expensive, their resources are almost always shared by severalusers. By using microprocessors for the central processing unit, manufacturers were able to develop much smaller and less expensive computers.By 1981, improvements in capabilities of microprocessors led to the development and introduction of the now famous IBMPersonal Computer(PC). The PC was different from existing mini computers and main-frame computers because it was intended for use by one person (single-user),and the software operating systems developed for the PC's (PC-DOS and MS-DOS) further limited the PC's to one user application program ata time (single-tasking). Performance improvements in existing characteristics such as operating frequency, address and data bus size, and chip in-tegration are considered evolutionary changes in microcomputers. For example, the operating frequency of microcomputers has increased fromone megahertz (MHz) to 33 MHz in the last 10 years. While this is a significant increase in operating frequency, 33 MHzis not even close to thecurrent state-of-the-art in supercomputers such as the Cray computers which operate in the 300 MHzrange. Of course, the Cray does not use123Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32Published by Arkansas Academy of Science, 1990

Image Enhancement of Faded Historic Documents

UARK (University of Arkansas )

Journal of the Arkansas Academy of Science Volume 44 Article 32 1990 Image Enhancement of Faded Historic Documents Robert Crisp Jr. University of Arkansas, Fayetteville Barry C. Wells University of Arkansas, Fayetteville Follow this and additional works at: https://scholarworks.uark.edu/jaas  Part of the Archival Science Commons Recommended Citation Crisp, Robert Jr. and Wells, Barry C. (1990) "Image Enhancement of Faded Historic Documents," Journal of the Arkansas Academy of Science: Vol. 44 , Article 32. Available at: https://scholarworks.uark.edu/jaas/vol44/iss1/32 This article is available for use under the Creative Commons license: Attribution-NoDerivatives 4.0 International (CC BY-ND 4.0). Users are able to read, download, copy, print, distribute, search, link to the full texts of these articles, or use them for any other lawful purpose, without asking prior permission from the publisher or the author. This General Note is brought to you for free and open access by ScholarWorks@UARK. It has been accepted for inclusion in Journal of the Arkansas Academy of Science by an authorized editor of ScholarWorks@UARK. For more information, please contact scholar@uark.edu. Proceedings Arkansas Academy of Science, Vol. 44, 1990 121GENERAL NOTESIMAGEENHANCEMENT OF FADED HISTORIC DOCUMENTSThe need to preserve historic documents is generally recognized and few would deny that these documents become more valuable with thepassage of time. Unfortunately, as time passes, the document becomes faded and/or tattered making it less and less legible. Methods are availableto increase the lifeof the original, but these often inhibit access. Facsimiles are often used to circumvent this problem. But many facsimiles pro-cedures have limitations; for example, a first generation copy is better than a second generation copy and successive copies lose information. Digital(or computerized) copies overcome many of the obstacles encountered with the present methods of preservation."Digitalcomputer image enhancement has proven highly useful in numerous fields. Remote sensing, astronomy, and medical diagnosticsin particular have experienced quantum leaps in performance through the introduction of this technology". (Asmus, John F., "Digital Image Pro-cessing in ArtConversion", BYTE, March 1987, p. 151). With a digital copy, the document can be viewed as having an extremely fine grid ofpoints. These points or dots (often called pixels) can be turned on or off in a simple "line art" copy, or they may have different intensities, orgray scales, to provide a copy ofblack and white photographs. Finally, they may have both intensity and color to provide a fullcolor copy. Thesecomputer generated copies have several advantages: 1) they do not exhibit degradation over time other than the risk (which can be minimized)of losing the copy or corrupting the data; 2) a tenth generation copy is as good as a first generation copy; 3) they can be easily exchanged by usingelectronic media or electronic transmission; and 4) most importantly, they lend themselves tocomputer indexing and retrieval so they may be retrievedin milliseconds and viewed on video screens.Traditional methods of image enhancement involve "gray scale reversal, stretching of gray levels, modification of the histogram to the desiredfunction, and so on". (Chellappa, Rama and Alexander A. Sawchuck, DigitalImage Processing and Analysis, Vol. 1, 1985, p. 426). Several areasof enhancement have emerged. These consist of optical character recognition, satellite imaging and medical photography, to name a few. As mostof these areas are unrelated, what is available today is a collection of algorithms and functions which may or may not apply to a given image.Aprimary obstacle of digital copies has been the very large amount of data (and associated cost) required for a copy. Several developmentshave occurred which lessen this problem: 1) computers are much faster and the speed is doubling about every 2 years; 2) the cost of storing digitaldata is dropping by half every 2 years. The development of data compression algorithms also significantly reduce the data storage requirements.Taken together, digital archives are a viable alternative today, and a near certainty for the future.This paper explores the unique problems associated with digitizing old documents that contain handwritten script. Additionally, a methodis suggested for accurately capturing the image data.This project consists of an interdisciplinary approach to providing an alternate method of document preservation. Several branches of thehumanities, coordinated with computer science and engineering at the University of Arkansas in Fayetteville willbe involved.The proposed project task force is centered around a newly formed History Technology Laboratory at the University ofArkansas. This groupconsists of a board which contains representation from engineering and the humanities. The humanities reprsentatives make up a majority of thegroup. History, library science and literature represent some disciplines within the humanities in this group.Many books and documents address the topic of image processing. Most of the existing image processing systems are expensive and difficultto access and use; however, many ofthe techniques and algorithms used in existing systems and described in current books can be utilized in this project.The National Archives and the Library of Congress are developing a similar type of imaging system. Recent contacts withpersonnel at theLibrary of Congress indicate that there are some complexities in their system. These larger systems typically are few in number and complicatedto use. One of the goals of this project willbe to produce a prototype which willbe cost effective and easy to use. The prototype should havethe capability of recovering difficult to read text and producing a facsimile which would be representative of the original document.This work was performed on a 386 based machine with a high resoluton (1,024 X 768) monitor. The output is from a 300 DPIHP LaserJet.Higher output densities are available but are not yet implemented. Alternate storage devices (tape, optical disk, etc.) are being evaluated and effortsare underway to find or create an image database front end.A typical old document contains nothing other than freehand script. Typically, the quality of the paper and the legibility of the text varythroughout the entire length and width of the document. Thus, some parts of the page willbe clearly legible while other parts may be totally illegi-ble. Refer to Fig. 1. "Abasic tool utilized in performing subjective enhancement and image analysis is the image histogram. The histogram revealsthe distribution of digitized intensity within an image....". (Green, William B., DigitalImage Processing, A Systems Approach, 2nd ed., p. 64).Since each document has such variations as described above, difficultyoften exists when applying a single algorithm to the entire histogram. Anyenhancement scheme which applies to the entire document must take this into account.Existing systems are rarely applicable in this situation. Optical character recognition, satellite and medical imaging contribute concepts andgeneral guides to script enhancement but do not provide a total solution. Algorithms which affect the entire page can be utilized to improve thequality of a document to some degree. The algorithms utilized on the letter in Fig. 1 were (in order): 1) adjusted brightness, 2) adjusted contrast,3) performed linear equalization and 4) sharpened the image. The algorithms produced Fig. 2. Notice that there are 2 horizontal areas splittingthe document into thirds. These are folds in the paper. To make matters worse, at some time in the past scotch tape was applied to approximatelytwo-thirds of these areas starting at the left edge. Figure 3 displays a blowup of part of the lower band. (The vertical and horizontal measurementswere altered automatically by the software in an attempt to fit the picture on a single page.) Figures 4 and 5 represents a best attempt to clarifythe words underneath the scotch tape. The letters barely become readable in Fig. 6.The intent is to create a proximity algorithm to locate and enhance line segments. Figure 7 shows the desired end result. Lines will typicallyhave characteristics which distinguish them from other marks. Lines willnormally be ofa consistent gray level in a continuous fashion and furtherwillnot be "very wide". These features will allow the algorithm to discern the difference between the background and the line.The first 75 (V* inches at 300 DPI) rows of pixels are read into the computer memory from the image file. The entire document cannot beread at once due to hardware and software requirements. The algorithm must then perform 2 functions. The first executes the necessary stepsrequired to locate a line segment. The second "traces" the line segment and records the locations of those pixels which are recognized as partof a line into a table. The remaining pixels are then turned to white. The information is written back out to disk after performing these 2 steps.The script may then be enhanced through the use of readily available software by adjusting brightness and contrast levels.Script detection on older manuscripts has been discussed with relationship to existing enhancement systems. Inolder manuscripts, existingalgorithms proved inadequate. The need for new algorithms led to the formation ofan History /Technology Laboratory. The purpose of the laboratoryin regards to this project was to establish algorithms which are specific to script detection. Investigation of present technology led to the develop-ment of a proximity algorithm which locates and "traces" a line segment. This paper also included an example of an enhanced document.ROBERT M. CRISP, JR., Computer Science Engineering Department, Engineering 313, University ofArkansas, Fayetteville, AR 72701 and BARRYC. WELLS, Acxiom, Inc., GENESIS Program, University of Arkansas, ERC 214, Fayetteville, AR 72701.21Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32Published by Arkansas Academy of Science, 1990122Proceedings Arkansas Academy of Science, Vol. 44, 1990Arkansas Academy of ScienceJ§|§j| ' A--vt-(~£~ -'' -iJll- ' '" "' c""1 L-''''¦'''' ' -y ¦ "" 'V-r-C.._ //';„/ /<':'*-'¦-' /// /'; »'?' ;''' ' / «' i'tri Lt-''./—'.'-.>¦¦',¦' ¦ . "'y' t/1*1 !rr f .¦ h"..(*¦ 0 f'T'-,-Kf .iff • '¦ ¦>>^- \; «Figure 1. Original document produced in 1900 Figure 2. Original document after adjusting brightness and contrast,applying linear equalization and sharpening the image.9H9HI HBHHHHHH HIKK9MI wwutou-X.'us." 1 JLM'* ¦ • ¦''K» MiriBHUMBMiJem iBiiHH^u£I2LW:iITinililffflill^^ 'it/ /'i7 r i // /Nfr / / / .#' .Figure 3. Small section of original document Figure 4. Figure 3 after applying threshold filter122Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32https://scholarworks.uark.edu/jaas/vol44/iss1/32Proceedings Arkansas Academy of Science, Vol. 44, 1990 123General NotesFigure 5. Figure 4 after applying equalization and sharpnessFigure 7. Desired end result after applying proximity algorithmFigure 6. Figure 5 after applying contrast and brightnessTHE IMPACT OF MICROPROCESSOR PROTECTED MODE PROGRAMMINGON UNDERGRADUATE EDUCATION INENGINEERING TECHNOLOGYThe purpose of this paper is to examine some of the rapid changes that have recently occurred (and are continuing to occur) in microcom-puters and the impact of these changes on both faculty and students in engineering, technology, and related fields—such as physics, biology,mathematics, and chemistry.A microcomputer is any computer that uses a microprocessor for its central-processing-unit (CPU). In fact, a "microprocessor" can be describedor defined as a CPU on one integrated circuit or "chip." Because of their small size and low cost, microprocessors, which were first developedin 1971, have revolutionized the computer industry. Before the advent of microprocessors, all computers were generally classified as main-frameor minicomputers. Since main-frame and mini computers are usually very large and expensive, their resources are almost always shared by severalusers. By using microprocessors for the central processing unit, manufacturers were able to develop much smaller and less expensive computers.By 1981, improvements in capabilities of microprocessors led to the development and introduction of the now famous IBMPersonal Computer(PC). The PC was different from existing mini computers and main-frame computers because it was intended for use by one person (single-user),and the software operating systems developed for the PC's (PC-DOS and MS-DOS) further limited the PC's to one user application program ata time (single-tasking). Performance improvements in existing characteristics such as operating frequency, address and data bus size, and chip in-tegration are considered evolutionary changes in microcomputers. For example, the operating frequency of microcomputers has increased fromone megahertz (MHz) to 33 MHz in the last 10 years. While this is a significant increase in operating frequency, 33 MHzis not even close to thecurrent state-of-the-art in supercomputers such as the Cray computers which operate in the 300 MHzrange. Of course, the Cray does not use123Journal of the Arkansas Academy of Science, Vol. 44 [1990], Art. 32Published by Arkansas Academy of Science, 1990

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Image Enhancement of Faded Historic Documents

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