PDFlib Text Extraction Toolkit (TET) Manual

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} double yDpi = 72 * height / tet.height; ... Note that dpi values for rotated or skewed images may be meaningless. Full code for image dpi calculations can be found in the determine_image_resolution topic in the TET Cookbook. 84 Chapter 7: Image Extraction
7.3 Image Analysis Image merging. Sometimes it is not desirable to extract images exactly as they are represented in the PDF document: in many situations what appears to be a single image is actually a collection of several smaller images which are placed close to each other. There are some common reasons for this image fragmentation: > Some applications and drivers convert multi-strip TIFF images to fragmented PDF images. The number of strips can range from dozens to hundreds. > Some scanning software divides scanned pages in smaller fragments (strips or tiles). The number of fragments is usually not more than a few dozen. > Some applications break images into small pieces when generating print or PDF output. In extreme cases, especially documents created with Microsoft Office applications, a page may contain thousands of small image fragments. TET’s image merging engine detects this situation and recombines the image parts to form a larger and more useful image. Several conditions must be met in order for images to be considered as candidates for merging: > The image fragments are oriented horizontally or vertically (but not at arbitrary angles), and form a rectangular grid of sub-images. > The number of bits per component must be the same. > The colorspace must be the same or compatible. > Some combinations of colorspace and compression scheme (in particular, JPEG 2000 compression) prevent image merging. If the merging candidates can be combined to a larger image, they will be merged. Merged images can be identified as such by the images[ ]/mergetype pCOS pseudo object: it will have the value 1 (artificial) for merged images and 2 (consumed) for images which have been consumed by the merging process. Consumed images should generally be ignored by the receiving application. In order to completely disable image merging use the following page option: imageanalysis={merge={disable}} Fig. 7.2 Although this image consists of many little strips, TET will extract it is a single reusable image. 7.3 Image Analysis 85
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PDFlib GmbH München, Germany www.p
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Contents 0 First Steps with TET 7 0
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10.9 Option Handling 151 10.10 pCOS
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0.2 Applying the TET License Key Us
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1 Introduction The PDFlib Text Extr
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may extract some text which is not
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2 TET Command-Line Tool 2.1 Command
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Constructing TET command lines. The
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Extract images and generate TETML i
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3 TET Library Language Bindings Thi
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TET_CATCH(tet) { printf("Error %d i
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3.4 COM Binding Installing the TET
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3.6 .NET Binding The .NET edition o
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3.8 PHP Binding Installing the TET
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3.9 Python Binding Installing the T
Page 33 and 34: Exception Handling in RPG. TET clie
Page 35 and 36: 4 TET Connectors TET connectors pro
Page 37 and 38: 4.2 TET Connector for the Lucene Se
Page 39 and 40: Indexing metadata fields. The TET c
Page 41 and 42: 4.4 TET Connector for Oracle The TE
Page 43 and 44: these options on the command line.
Page 45 and 46: TET PDF IFilter is freely available
Page 47 and 48: tracts text and metadata from the P
Page 49 and 50: 5 Configuration 5.1 Indexing protec
Page 51 and 52: 5.2 Resource Configuration and File
Page 53 and 54: tet/3.0/resource /tet/3.0/resource/
Page 55 and 56: Geometry. The geometry features may
Page 57 and 58: 6 Text Extraction 6.1 Document Doma
Page 59 and 60: How to search with Acrobat 8/9: not
Page 61 and 62: 6.2 Unicode Concepts Unicode encodi
Page 63 and 64: artificial characters which will be
Page 65 and 66: width (x, y) beta fontsize baseline
Page 67 and 68: 6.4 Support for Chinese, Japanese,
Page 69 and 70: Options for text filtering. There a
Page 71 and 72: 6.6 Content Analysis PDF documents
Page 73 and 74: Dehyphenation. Hyphenated words at
Page 75 and 76: Table 6.3 Document styles docstyle=
Page 77 and 78: Fig. 6.5 Sample font reports create
Page 79 and 80: glyphmapping {{fontname=Warnock* to
Page 81 and 82: 7 Image Extraction 7.1 Image Extrac
Page 83: 7.2 Image Geometry Using TET_get_im
Page 87 and 88: 7.4 Restrictions and Caveats Image
Page 89 and 90: 8 TET Markup Language (TETML) 8.1 C
Page 91 and 92: Depending on the sele
Page 93 and 94: You can specify the amount of text
Page 95 and 96: Table 8.3 TETML elements TETML elem
Page 97 and 98: 8.4 Transforming TETML with XSLT Ve
Page 99 and 100: Run the program as follows: nxslt3.
Page 101 and 102: 8.5 XSLT Samples The TET distributi
Page 103 and 104: Alphabetical list of words in the d
Page 105 and 106: 9 The pCOS Interface The pCOS (PDFl
Page 107 and 108: 9.2 Handling Basic PDF Data Types p
Page 109 and 110: 9.3 Composite Data Structures and I
Page 111 and 112: Path prefixes. Prefixes can be used
Page 113 and 114: Table 9.3 Universal pseudo objects
Page 115 and 116: Table 9.4 Pseudo objects for PDF ob
Page 117 and 118: Table 9.5 Pseudo objects for resour
Page 119 and 120: 9.6 Encrypted PDF Documents pCOS su
Page 121 and 122: 10 TET Library API Reference 10.1 O
Page 123 and 124: 10.2 General Functions Perl PHP res
Page 125 and 126: Returns Scope Bindings The converte
Page 127 and 128: 10.3 Exception Handling C++ string
Page 129 and 130: 10.4 Document Functions C++ int ope
Page 131 and 132: Table 10.3 Document options for TET
Page 133 and 134: C++ C int open_document_callback(vo
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Table 10.5 Page options for TET_ope
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Table 10.6 Suboptions for the conte
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Table 10.7 Suboptions for the layou
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Table 10.9 Suboptions for the struc
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C++ const TET_char_info *get_char_i
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10.7 Image Retrieval Functions C++
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C++ int write_image_file(int doc, i
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10.8 TET Markup Language (TETML) Fu
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10.9 Option Handling C++ void set_o
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10.10 pCOS Functions The full pCOS
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If the object has type stream all f
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A TET Library Quick Reference The f
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B Revision History Revision history
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unsupported types 87 XMP metadata 8
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