QUALITY REVIEW OF DOCUMENT IMAGES

Contents:

• Introduction
• Image Types, File Formats and Compression
• Viewing Software
• Accuracy Rate Requirements
• Cropping, Rotation, and Skewing
• Making a Preliminary Sample List
• Examining Bitonal Images
• Examining Grayscale Images
• Accepting and Rejecting Batches
• Glossary



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Introduction

The purpose of this training guide is to describe for the image reviewer the imaging process, provide basic information about imaging, document the standards for quality review of images, and define terms related to the imaging process. The guide is divided into six components, including this introduction, with each component addressing specific topics related to performing quality review on paper or microfilm document images.

The scanning of paper and microfilm items is done by outside contractors. Because paper items cannot leave the premises, the contractor for paper scanning has staff located on-site. The microfilm contractor scans a duplicate microfilm shipped to them by National Digital Library (NDLP). The contractors capture the digital images, perform post-processing, and then return the images to NDLP for review. At that point, we have three weeks in which to conduct our review.

The first step of the quality review process is done by a central receipt and review unit that runs a software called NDLView to check file header information (hidden tags not seen when just looking at the document itself)and whether the file opens. If the image batch passes NDLView, it is logged into the workflow tracking database and passed along to the appropriate division, indicated by the batch name e.g. in sigrb001 the rb stands for rarebook. The batch name prefix indicates the contractor, SIG is Systems Integration Group in this example, and the digits represent the sequence of the delivery. In addition, the prefix indicates the type of file received. Image files begin with either "sig" or "pr" (for Preservation Resources, the microfilm scanner)whereas a sgml text batch begins the initials of the text converter - either "dcl" for Digital Conversion Laboratory or "tbk" for Techbook.

After a division performs quality reveiw, a response of either acceptance or a request for rework is sent to the contractor. If rework is requested, then the contractor makes another delivery of specific itmes mentioned in the rework request, or the entire batch.


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