ASTM E2825-21

Standard Guide for Forensic Digital Image Processing

SIGNIFICANCE AND USE
5.1 Processed images are used for many purposes by the forensic science community. They can yield information not readily apparent in the original image, which can assist an expert in drawing a conclusion that might not otherwise be reached.  
5.2 This guide addresses image processing and related legal considerations in the following three categories:  
5.2.1 Image enhancement,  
5.2.2 Image restoration, and  
5.2.3 Image compression.
SCOPE
1.1 This guide provides digital image processing guidelines to ensure the production of quality forensic imagery for use as evidence in a court of law.  
1.2 This guide briefly describes advantages, disadvantages, and potential limitations of each major process.  
1.3 This standard cannot replace knowledge, skills, or abilities acquired through education, training, and experience, and is to be used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 30-Sep-2021
• ICS: 07.140 - Forensic science
• ICS: 35.140 - Computer graphics
• Technical Committee: E30 - Forensic Sciences
• Drafting Committee: E30.12 - Digital and Multimedia Evidence

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2825 − 21 An American National Standard
Standard Guide for
1
Forensic Digital Image Processing
This standard is issued under the fixed designation E2825; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
3
1. Scope 2.2 ISO/IEC Standard:
ISO/IEC 10918-1:1994 Information technology—Digital
1.1 This guide provides digital image processing guidelines
compression and coding of continuous-tone still images:
to ensure the production of quality forensic imagery for use as
Requirements and guidelines (JPEG) (also published as
evidence in a court of law.
CCITT Recommendation T.81 (1992))
1.2 This guide briefly describes advantages, disadvantages,
3. Terminology
and potential limitations of each major process.
3.1 Definitions—For definitions of terms relating to this
1.3 This standard cannot replace knowledge, skills, or
standard, refer to Terminologies E1732 and E2916.
abilities acquired through education, training, and experience,
and is to be used in conjunction with professional judgment by
4. Summary of Practice
individuals with such discipline-specific knowledge, skills, and
4.1 The original image shall be preserved. Any image
abilities.
processing should be applied only to a working copy of the
1.4 This standard does not purport to address all of the
image.
safety concerns, if any, associated with its use. It is the
4.2 Any changes made through image processing shall meet
responsibility of the user of this standard to establish appro-
the following criteria:
priate safety, health, and environmental practices and deter-
4.2.1 Processing steps are documented in a manner suffi-
mine the applicability of regulatory limitations prior to use.
cient to permit a comparably trained person to understand the
1.5 This international standard was developed in accor-
steps taken, the techniques used, and extract comparable
dance with internationally recognized principles on standard-
information from the image; and
ization established in the Decision on Principles for the
4.2.2 The end result is presented as a processed or working
Development of International Standards, Guides and Recom-
copy of the image.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
4.3 Avoid the introduction of artifacts that add misleading
information to the image or the loss of image detail that could
2. Referenced Documents
lead to an erroneous interpretation.
2
2.1 ASTM Standards:
5. Significance and Use
E1732 Terminology Relating to Forensic Science
E2916 Terminology for Digital and Multimedia Evidence 5.1 Processed images are used for many purposes by the
Examination forensic science community. They can yield information not
readily apparent in the original image, which can assist an
expert in drawing a conclusion that might not otherwise be
reached.
5.2 This guide addresses image processing and related legal
considerations in the following three categories:
5.2.1 Image enhancement,
5.2.2 Image restoration, and
1
This guide is under the jurisdiction of ASTM Committee E30 on Forensic
5.2.3 Image compression.
Sciences and is the direct responsibility of Subcommittee E30.12 on Digital and
Multimedia Evidence.
6. Image Enhancement
Current edition approved Oct. 1, 2021. Published October 2021. Originally
approved in 2012. Last previous edition approved in 2019 as E2825 – 19. DOI:
6.1 Image enhancement is any process intended to improve
10.1520/E2825-21.
the visual appearance of an image.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
3
Standards volume information, refer to the standard’s Document Summary page on Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
the ASTM website. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2825 − 21
6.1.1 Use brightness adjustment when the image is too 6.1.7 Use nonlinear contrast adjustments to adjust the con-
bright or too dark. If the image is made too bright, there is a trast in selected brightness ranges within the image. These
risk of loss of detail in light areas. If the image is made too include gamma correction, grayscale transformation, and the
dark, there is a risk of loss of detail in
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2825 − 19 E2825 − 21
Standard Guide for
1
Forensic Digital Image Processing
This standard is issued under the fixed designation E2825; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This guide provides digital image processing guidelines to ensure the production of quality forensic imagery for use as
evidence in a court of law.
1.2 This guide briefly describes advantages, disadvantages, and potential limitations of each major process.
1.3 This standard cannot replace knowledge, skills, or abilities acquired through education, training, and experience, and is to
be used in conjunction with professional judgment by individuals with such discipline-specific knowledge, skills, and abilities.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of
regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2
2.1 ASTM Standards:
E1732 Terminology Relating to Forensic Science
E2916 Terminology for Digital and Multimedia Evidence Examination
1
This guide is under the jurisdiction of ASTM Committee E30 on Forensic Sciences and is the direct responsibility of Subcommittee E30.12 on Digital and Multimedia
Evidence.
Current edition approved June 1, 2019Oct. 1, 2021. Published June 2019October 2021. Originally approved in 2012. Last previous edition approved in 20182019 as E2825
– 18.19. DOI: 10.1520/E2825-19.10.1520/E2825-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E2825 − 21
3
2.2 ISO/IEC Standard:
ISO/IEC 10918-1:1994 Information technology—Digital compression and coding of continuous-tone still images: Requirements
and guidelines (JPEG) (also published as CCITT Recommendation T.81 (1992))
3. Terminology
3.1 Definitions—For definitions of terms relating to this standard, refer to Terminologies E1732 and E2916.
4. Summary of Practice
4.1 The original image shall be preserved. Any image processing should be applied only to a working copy of the image.
4.2 Any changes made through image processing shall meet the following criteria:
4.2.1 Processing steps are documented in a manner sufficient to permit a comparably trained person to understand the steps taken,
the techniques used, and extract comparable information from the image; and
4.2.2 The end result is presented as a processed or working copy of the image.
4.3 Avoid the introduction of artifacts that add misleading information to the image or the loss of image detail that could lead to
an erroneous interpretation.
5. Significance and Use
5.1 Processed images are used for many purposes by the forensic science community. They can yield information not readily
apparent in the original image, which can assist an expert in drawing a conclusion that might not otherwise be reached.
5.2 This guide addresses image processing and related legal considerations in the following three categories:
5.2.1 Image enhancement,
5.2.2 Image restoration, and
5.2.3 Image compression.
6. Image Enhancement
6.1 Image enhancement is any process intended to improve the visual appearance of an image.
6.1.1 Use brightness adjustment when the image is too bright or too dark. If the image is made too bright, there is a risk of loss
of detail in light areas. If the image is made too dark, there is a risk of loss of detail in the dark areas.
6.1.2 Use color processing to modify the color characteristics of objects within an image. This includes color space
transformations, pseudocoloring, and hue
...