Image Capturing
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Capturing the Image (Digital Imaging) $4.49 |
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Capturing the Image (Digital Imaging) by Joe Farace $9.95 |
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Capturing the Image (Digital Imagin By Joe Farace $2.99 |
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Capturing the Image (Digital Imaging) by Joe Farace $7.80 |
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American Photographers: Capturing the Image Collective $0.99 |
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Capturing the Criminal Image: From Mug Shot to Surveill $36.97 |
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NEW BOOK Capturing the Image $5.00 |
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The Rock-Art of Eastern North America: Capturing Images $63.13 |
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Capturing the Criminal Image: From Mug Shot to Surveill $105.52 |
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NEW BOOK Capturing the Image $9.99 |
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Capturing the Friedmans Art Poster Print $24.99 Title: Capturing the Friedmans. Image Size: 11 in. x 17in. Paper Size: 11 in. x 17in. Art Poster PRINTWe have an unparalleled selection of both vintage and modern prints, posters, art prints, photographs and framed imagery. Our selections are ideal for both the office and home and we have over 400,000 images available for search or browsing. Your print is presented on premium, high grade paper an… |
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Capturing the Friedmans Art Poster Print $24.99 Title: Capturing the Friedmans. Image Size: 11 in. x 17in. Paper Size: 11 in. x 17in. Art Poster PRINTWe have an unparalleled selection of both vintage and modern prints, posters, art prints, photographs and framed imagery. Our selections are ideal for both the office and home and we have over 400,000 images available for search or browsing. Your print is presented on premium, high grade paper an… |
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Capturing the Friedmans Art Poster Print $74.99 Title: Capturing the Friedmans. Image Size: 43 in. x 62in. Paper Size: 43 in. x 62in. Art Poster PRINTWe have an unparalleled selection of both vintage and modern prints, posters, art prints, photographs and framed imagery. Our selections are ideal for both the office and home and we have over 400,000 images available for search or browsing. Your print is presented on premium, high grade paper an… |
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The Trial $29.99 Orson Welles’s 1962 take on Franz Kafka’s nightmare comedy stars Anthony Perkins as a twitchy K, a man accused of a crime that is never specified. The story has been filmed several times over the years, but not quite with the air of noir fable Welles brings to it. Beginning with an unexpected prologue in which Welles, in voiceover, tells a haunting parable while we look at artwork by pioneer … |
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The Golandsky Institute: Lecture/demonstration, Paul Roberts Impressionism: Capturing the Illusive Image $29.00 Distinguished Presenter Series Impressionism: Capturing the Illusive Image Highly acclaimed British author and pianist Paul Roberts was guest speaker at the 2005 Golandsky Institute Summer Symposium at Princeton University. The Institute’s Distinguished Presenters Series is privileged to include among its offerings this fascinating lecture/demonstration by one of the world’s leading interpreters… |
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Elgato 10020196 Turbo.264 HD Encoder/Accelerator $85.91 Item #: 44433N. Turbo.264 HD converts video files to a format that can be played on an iPod, iPhone, and Apple TV, used on a computer, and shared on the web. Device Type: Video converter – externalInterface Type: Hi-Speed USBDimensions (WxDxH): 1.2 in x 2.9 in x 0.4 inWeight: 0.6 ozVideo Input: Hi-Speed USB – externalVideo Modes: 1080pDigital Video Format: MPEG-1, MPEG-2, MPEG-4, QuickTime, AVI, D… |
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Stereo-Zoom Trinocular Video Inspection System with Dual Arm Boom Stand, Image Capturing Software, a … |
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Ample Scientific TCA-3.0PACK 3.0 MP Digital Microscope CMOS Camera With Image Capturing And Processing Software $261.00 The TCA-3.0PACK Digital CMOS microscope camera is excellent for education, and is a must-have for those who wishes to document their findings under a microscope. Standard C-mount and additional adaptors allows this unit to be used on almost all microscopes on market – both biological and stereo microscopes! This unit provides outstanding color resolution and sensitivity, and intuitive software mak… |
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Print Shop 21 Pro Publisher Deluxe Digital Imaging Suite $129.99 Two great products in one box. The Print Shop 21 Pro Publisher Deluxe Digital Imaging Suite combines the powerful desktop publishing you need to create all of your business communications PLUS the advanced photo editing features you need to manage and transform your vast photo collection. Whether for business or home use, these two products offer a total productive creative solution. Over 345,00… |
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Digital Astrophotography: A Guide to Capturing the Cosmos $16.99 At first glance, the challenge of astrophotography may appear daunting. But not only are spectacular results possible, they are easy to learn with the step-by-step instructions provided in Stephan Seip’s Digital Astrophotography: A Guide to Capturing the Cosmos. Today, amateurs can produce images that only twenty years ago a large professional observatory would have been proud of; and this book sh… |
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N-force Marine Nightvision Waterproof Scope $167.44 This nightvision scope is perfect for all-weather viewingThis night spotting scope is 100-percent water tight and actually floatsThis infrared system captures night images from up to 300 meters away |
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Capturing the Criminal Image (Paperback) $22.28 At the beginning of the twentieth century, criminals, both alleged and convicted, were routinely photographed and fingerprinted-and these visual representations of their criminal nature were archived for possible future use. At the beginning of… |
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Fine Art Wedding Photography (Paperback) $21.31 Description not available. |
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Sharper Image 10×25 Digital UV Binoculars/ Camera $36.99 The Sharper Image 10×25 Digital Camera/ Binocular offers a powerful, compact binocular for crystal-clear views. This pair of binoculars can actually capture those beautiful sights and memorable moments you zoom in on. |
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Sharper Image 10×25 Digital UV Binoculars/ Camera $36.99 The Sharper Image 10×25 Digital Camera/ Binocular offers a powerful, compact binocular for crystal-clear views. This pair of binoculars can actually capture those beautiful sites and memorable moments you zoom in on. |
Image Processing
Documents that are scanned for image processing or storage are often captured at 8 bits per pixel. These are referred to as grayscale images in that 256 levels of gray are able to be represented in the image. The capability to represent shades of gray is required to faithfully capture photographs and graphics but is not normally needed for text. Consequently, scanned images are often binarized. This process involves the selection of a threshold value and then changing all pixel values below that threshold to black and all pixel values above the threshold to white. This compresses the image by only requiring 1 bit per pixel instead of 8 bits per pixel. For example, an 8.5 inch by 11 inch document scanned at 200 samples per inch, has its storage requirement drop from 3.6 megabytes to 450 kilobytes. Binarization also occurs when documents are transmitted by fax as images are created that are represented with 1 bit per pixel as well.
Given a proper threshold, binarized images that contain text can normally still be read by either human eye or OCR algorithms. Indeed, some OCR algorithms begin the OCR process by binarizing the image as the text is typically dark against a lighter background. However, if bar codes are present within the binarized image, they can by altered enough by the binarization process to cause difficulty for a decode algorithm. The image to the left (http://www.omniplanar.com/_upload/CodePics/Code39-GreyscaleWeb.gif) shows part of the start pattern of a Code 39 linear bar code. The top portion shows the image represented as 8 bits per pixel, while the lower portion shows a binarized version using a threshold of 100. Note that the smooth transitions from white to black in the grayscale image have been transformed into ragged edges that have plus or minus one pixel variability. As a result, the width of each bar or space can vary by plus or minus 2 pixels. Given that the information in linear bar codes is contained in the widths of the bars and spaces, decode problems can result depending on the size and type of the original bar code symbol. The remainder of this article will focus on two issues that should be considered to improve the read rate of binarized bar codes: sample density and symbology type.
Sample Density
Sample density is the number of samples per unit area that an image is captured. Typical sample densities used for document processing range from 200 to 300 samples per inch (dots per inch or DPI). Fax transmission can vary from 100 up to 400 DPI. In bar code decoding, a more important parameter to consider is the samples per module, where the module size is the size of the smallest feature of the bar code. This distance is also referred to as the X dimension. This parameter includes both the sample density of the image capture device along with the size of the bar code being scanned. If a bar code decoding software toolkit requires a minimum of 1.6 pixels per module for linear bar codes in a grayscale image. From above, if the width of a bar or space can vary by 2 pixels after binarization, one can see that problems can exist in the short widths at this low sample density. Consequently, it is recommended that a typical value of 4 pixels per module for bar codes that will be binarized. For a document scanned at 200 DPI, this requires a minimum module size in the printed bar code of .020 inchs or 20 mils. Increasing the samples per module beyond 4 is also recommended for images that will go through multiple binarization processes such as documents that will be faxed multiple times.
Symbology Type
The choice of symbology used to encode data should also be considered carefully. Linear (or 1D) bar codes can be broadly classified into two distinct groups: wide/narrow codes and multiple width codes. In a wide/narrow code, each bar or space can only be either narrow or wide. The wide to narrow ratio, which gives the size ratio between the two widths, typically ranges from 2 to 3. Popular symbologies that use only 2 widths include Code 39 and Interleaved 2 of 5. Multiple width codes have more than 2 possible choices for the widths of bars and spaces. Popular symbologies that employ more than two possible widths include UPC and Code 128, both of which allow a bar or space to be either 1, 2, 3, or 4 modules. Given the same samples per module, wide/narrow symbologies typically survive the binarization process with higher read rate performance than their multiple width counterparts. This is simply due to the fact that in the presence of edge variation due to binarization, it is easier to determine if a run is X or 3X wide (where X is the length of a module and an assumed wide to narrow ratio of 3) or if it is 1X, 2X, 3X or 4X as is the case with multiple width symbologies. The table below classifies some popular linear symbologies into the two classes mentioned above.
Wide/Narrow
Codabar
Code 39
Interleaved 2 of 5
Patch Code
Multiple Width
Code 128
Code 93
RSS
UPC
While wide/narrow symbologies are preferred in applications where binarization will occur, they do not normally have as high a data density (data stored per unit width) compared to multiple width symbologies with the same X dimension. This can be an issue where limited space on the document is provided for the bar code symbol.
2D Symbologies
2D (or two-dimensional) matrix symbologies are typically presence/absence codes. They use a regular grid of possible cell positions, and the presence or absence of a cell in a grid location encodes the data. Two-dimensional symbols have much higher data density than 1D codes as information is stored in both dimensions of the symbol. In addition, they normally provide error correction to provide redundancy in case some cell data values can not be determined. When a 2D symbol is binarized with sufficient samples per module (the size of a grid position), they tend to do better than linear codes as the edge information is not as critical: it is the position of the center of the cell that is more important. Decoding software may require a minimum of 2.75 pixels per module in a grayscale image for reliable operation. If additional samples per module beyond 2.75 is provided, performance continues to improve and is a good choice for images that will undergo multiple binarizations. A sample density of 5 pixels or more for 2D matrix symbologies gives good read performance after binarization. Popular 2D Matrix codes include Data Matrix, QR Code, and Aztec Code.
PDF417 is often referred to as a 2D symbology. However, it is not a true matrix code. It is a stacked linear code, consisting of multiple rows of short linear codewords. It allows bars and spaces to have up to 6 different widths and as such it can be adversely affected by binarization at lower samples per module.
Summary
In applications where scanned documents containing bar codes are to be binarized, read rate performance can be improved by using linear symbologies that employ only wide/narrow choices for bars and spaces along with at least 4 or more pixels per module. Two-dimensional matrix codes are a good choice when binarization is used with a minimumof 5 pixels per module, and they provide the added benefit of increasing data density of the bar code symbol.
About the Author
With over 17 years of experience in the bar code industry, Bob Dunphy has been Principal Engineer at Omniplanar, Inc (
http://www.omniplanar.com
) since its inception. He has designed numerous CCD camera systems as well as high speed processing platforms.
Contour Reality Capture
Tags: image capturing, image capturing devices, image capturing methods, image capturing program, image capturing robot, image capturing software, image capturing system, screenshot, software, tools, video, web, web2.0