Adobe 22101156 - Acrobat Capture - PC User manual

50
Online Guide
• Commands
• Using the Capture plug-in
• Capturing documents
• Correcting captured documents
• Setting Capture plug-in
preferences
• Troubleshooting
Adobe
®
Acrobat
®
Capture Plug-In

51
Commands
Capturing docu-
Setting Capture
Correcting captured docu-
To review and correct sus-
File
Capture...Preferences
Document
Capture Pages...
Edit
Show Capture Suspects
Find First Suspect

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Using the Capture plug-in
You use the Capture plug-in when you choose the
Capture Pages command in Acrobat Exchange. The
plug-in uses optical character recognition (OCR) to
convert bitmap text to text that can be corrected,
indexed, searched, or copied to other files. The text
it converts is in PDF image documents that were
scanned directly, or imported, into Acrobat. For
information about these PDF documents, and about
the kinds of PDF documents produced by capturing
text from them, see
About PDF document styles
.
You can configure the Capture plug-in to recognize
any of eight languages, hide recognized text behind
a document image, and downsample images to
minimize file size. For more information, see
Setting Capture plug-in preferences
.
After you capture a document, you can use the
touch-up tool in Exchange to review and correct
text. See Correcting captured documents for
details.

53
The Capture plug-in is installed from the Acrobat
3.0 CD-ROM. For details on running the Acrobat
Installer, see the
Acrobat Getting Started Guide
.
Use the Capture plug-in to convert small collections
of paper documents and electronic images to PDF
directly from Acrobat Exchange. If you need to con-
vert large collections of paper documents or elec-
tronic images to PDF, consider upgrading to the full
Acrobat Capture product, which offers a number of
automated processing features and enhanced
reviewing capabilities.

54
About PDF document styles
Adobe Acrobat can produce three styles of PDF
documents:
•
PDF Image Only documents contain only a bitmap
picture of the original document. PDF Image Only files
are produced by the Scan and the Import commands in
Exchange. If you need to convert and view image files
quickly, PDF Image Only is sufficient.
•
PDF Normal documents contain electronic text that
is scalable and can be indexed, searched, and copied.
Page formatting and graphical images are preserved.
You can create this kind of file with Acrobat Distiller, PDF
Writer, or the Capture Pages command in Exchange. PDF
Normal files are significantly smaller than their PDF
Image Only counterparts, making them ideal for online
distribution.

55
•
PDF Original Image with Hidden Text documents
combine features of PDF Image Only and PDF Normal
documents. They contain a complete bitmap picture of
the original document, but with recognized text hidden
behind the picture. This provides the advantages of
searchable text while ensuring that a document is iden-
tical in appearance to the original. Use this kind of PDF
file when you are required to keep the original scanned
image of a document for legal or archival purposes. PDF
Original Image with Hidden Text files can be created
only with the Capture Pages command in Exchange.
When you capture a PDF Image Only file, it usually
reduces file size significantly. In most cases, PDF
files captured with the PDF Normal setting are
smaller than those captured with the PDF Original
Image with Hidden Text setting. For details, see
Comparing PDF file sizes
.

56
Capturing documents
The documents you capture are image files that
you have scanned or imported into Exchange—
PDF Image Only
files.
To capture a document:
1 Using Exchange, do one of the following:
•
To import an image file, choose File > Import > Image.
Select the file you want to import and click Open. See
Acrobat Exchange
for more information on importing
image files.
•
To scan a paper document, choose File > Scan.
Choose a scanner device and document type; then click
Scan. See
Acrobat Scan
for information on using a
scanner with Acrobat Exchange.
2 Choose Document > Capture Pages.
3 Determine which pages you want to capture by
selecting All Pages, Current Page, or Specified Range
and entering the page numbers in the text box.

57
4 If you want to change the Capture preferences,
click Preferences. The document will be captured
with the new settings. See
Setting Capture plug-in
preferences
for details.
5 Click OK. The Capture progress window shows the
page, character, and word recognition process. In order
for the process to be successful, the resolution of the
captured PDF Image Only file must fall within the follow-
ing ranges:
•
Monochrome images, 200–600 dpi
•
Grayscale or color images, 200–400 dpi
Also, the text should be dark against a light back-
ground. Text on a dark or shaded background, or on
a page with complex color gradients, may not be
recognized.

58
Correcting captured documents
When the Capture plug-in suspects it has not recog-
nized a word correctly, it displays the bitmap image
of the original word in the document and hides its
best guess for the word behind the bitmap. This
ensures accurate reproduction of the original, even
without correction.
You can review and correct
suspect
words in
Exchange with the touch-up tool. This is useful
when you want your document to be fully search-
able, for example, when indexing it for publication
on CD-ROM or the World Wide Web.
Note: The Capture plug-in uses the current PDF
Writer settings for font embedding and subsetting
when it creates PDF files. To avoid problems when
correcting a captured document, be sure that font
subsetting is not selected in PDF Writer before
capturing the document. See PDF Writer for more
information.

10
To view all the suspect words in a document:
Choose Edit > Show Capture Suspects. Each of the
suspect words in the document is highlighted.
To review and correct suspect words:
1 Choose Edit > Find First Suspect. The suspect text is
highlighted, and its bitmap image appears in the
Suspect Image window.
2 Choose from one of the following:
•
To accept the highlighted suspect text as correct,
click Accept (TAB). The bitmap image is discarded.
•
To leave the bitmap image in place, click Next
(Shift+TAB).
•
To edit the highlighted suspect text, type the correct
text; then click Accept (TAB). The text is changed, and
the bitmap image is discarded.
See
Acrobat Exchange
for more information on
using the touch-up tool.

60
Setting Capture plug-in preferences
Choose File > Preferences > Capture to control the
following Capture plug-in preferences:
•
Primary OCR Language indicates which language
dictionary is used to recognize words when documents
are captured.The Capture plug-in also uses a custom
dictionary, which you can modify. For more information,
see
Adding words to the custom dictionary
.
•
PDF Output Style specifies what kind of PDF docu-
ment the Capture plug-in creates. Two options are avail-
able: PDF Normal and PDF Original Image with Hidden
Text. See
About PDF document styles
for details.

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•
Downsample Images gives you the option of down-
sampling images in captured PDF documents, which can
be useful if you want to minimize file size. See
Choosing downsampling options
for details.
•
Location for Temporary Files specifies the direc-
tory where temporary files are stored during the capture
process. If you are running out of space in the specified
directory, you can change the location by typing a new
directory path.

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Adding words to the custom
dictionary
In addition to its standard language dictionaries,
the Capture plug-in uses a custom dictionary to
recognize words. You can add words to this custom
dictionary by editing the dictionary file.
To edit the custom dictionary (Windows):
1 Using a text editor such as Notepad, or a word
processor, open the custdict.spl file in the
Acrobat3\Capture directory. If you use a word
processor, open the file as a text file.
2 On a separate line, type each word you want to add.
Be sure that the list remains in alphabetical order.
3 Save the file. If you are using a word processor, save
the file as a text file.

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Choosing downsampling options
When you capture a document, you can choose to
downsample images in the captured document.
Doing this can significantly reduce file size. With
downsampling on, images are downsampled as fol-
lows:
• Black-and-white images are downsampled to 200dpi
(Image less than 300 dpi are not downsampled)
•
Grayscale and color images are downsampled to 150
dpi (Images less than 225 dpi are not downsampled)
Note: When both the PDF Original Image + Text
and downsampling options are selected, color and
grayscale page images are downsampled below
200 dpi. Consequently, you will not be able to
reprocess the resulting files with Capture.

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To turn downsampling on or off:
1 Choose File > Preferences > Capture or Document >
Capture Pages, and click the Preferences button.
2 Select or deselect the Downsample Images option as
desired. (Downsampling is on by default.)
Note: The Downsampling Images setting in
Capture Preferences overrides the downsampling
setting in PDF Writer.

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Comparing PDF file sizes
Consider file size when planning work flow or pub-
lishing documents online. Larger files (especially
24-bit color ones) take more time to capture, send
over networks, and display on-screen.
The two charts on the following pages show the file
sizes resulting from the import and capture of an
8 1/2-by-11 inch page containing text, line art, and
a photograph.These charts show how the PDF Out-
put Style you choose can effect the size of the final
PDF file.
Note: The Capture plug-in uses PDF Writer to cre-
ate PDF files, but you cannot change PDF Writer
compression settings to reduce the size of captured
files. The Capture plug-in always uses the default
PDF Writer compression settings.

17
Example file used for charts on following two pages

67
Captured file sizes: downsampling on
In most cases, the size of a captured file is significantly reduced when downsam-
pling is turned on in the Capture preferences.
Image type
Scanned at
300 dpi
TIFF image file
(original file)
uncompressed
compressed
PDF Image
Only
PDF Normal PDF
Original
Image +
Hidden Text
Black and white 1043K
LZW 190K
Group 4 201K
202K 61K 94K
4-bit grayscale 8335K
LZW 606K
421K 222K 325K
8-bit grayscale 8333K
LZW 1343K
1183K 113K 309K
8-bit indexed color 8335K
LZW 796K
612K 364K 477K
24-bit RGB color 24998K
LZW 3085K
2531K 500K 616K

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Captured file sizes: downsampling off
The file in this chart was processed with downsampling turned off in the Capture
preferences. (Turning downsampling on could reduce the file size even more). In
some cases, a PDF Original Image + Hidden Text file is smaller than the PDF Image
only file because the Capture plug-in uses additional compression methods.
Image type
Scanned at
300 dpi
TIFF image file
uncompressed
compressed
PDF Image
Only
PDF Normal PDF
Original
Image +
Hidden Text
Black and white 1043K
LZW 190K
Group 4 201K
202K 161K 213K
4-bit grayscale 8335K
LZW 606K
421K 222K 328K
8-bit grayscale 8333K
LZW 1343K
1183K 766K 884K
8-bit indexed color 8335K
LZW 796K
612K 366K 477K
24-bit RGB color 24998K
LZW 3085K
2531K 1832K 2044K

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 1996 Adobe Systems Incorporated. All rights reserved.
Adobe Acrobat 3.0 Capture Online Guide
This manual, as well as the software described in it, is furnished under license
and may be used or copied only in accordance with the terms of such license.
The content of this manual is furnished for informational use only, is subject to
change without notice, and should not be construed as a commitment by Adobe
Systems Incorporated. Adobe Systems Incorporated assumes no responsibility
or liability for any errors or inaccuracies that may appear in this book.
The copyrighted software that accompanies this manual is licensed to the End
User for use only in strict accordance with the End User License Agreement,
which the Licensee should read carefully before commencing use of the soft-
ware. Except as permitted by such license, no part of this publication may be
reproduced, stored in a retrieval system, or transmitted, in any form or by any
means, electronic, mechanical, recording, or otherwise, without the prior writ-
ten permission of Adobe Systems Incorporated.
Adobe, the Adobe logo, Acrobat, Acrobat Capture, the Acrobat logo, Distiller,
Acrobat Exchange, Adobe Type Manager, PostScript, and the tagline “If you can
dream it, you can do it” are trademarks of Adobe Systems Incorporated.
Microsoft and Windows are registered trademarks and ActiveX and Windows NT
are trademarks of Microsoft Corporation in the U.S. and other countries. Apple,
Macintosh, Power Macintosh, and QuickTime are registered trademarks and
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is a registered trademark of Lotus Development Corporation. Netscape and
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UNIX is a registered trademark in the U.S. and other countries, licensed exclu-
sively through X/Open Company, Ltd. Pentium is a trademark of Intel Corpora-
tion. All other products or name brands are trademarks of their respective
owners.
This product contains an implementation of the LZW algorithm licensed under
U.S. Patent 4,558,302.