OSAC 2022‐S‐0008

Standard Guide for Facial

Image Comparison

Documentation

Facial & Iris Identification Subcommittee

Digital/Multimedia Scientific Area Committee (SAC)

Organization of Scientific Area Committees (OSAC) for Forensic Science
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OSAC Proposed Standard

OSAC 2022‐S‐0008

Standard Guide for Facial Image

Comparison Documentation

Prepared by  

Facial & Iris Identification Subcommittee

Version: 2.0

February 2024

Disclaimer:

This OSAC Proposed Standard was written by the Facial & Iris Identification Subcommittee of the

Organization of Scientific Area Committees (OSAC) for Forensic Science following a process that

includes an open comment period. This Proposed Standard will be submitted to a standard

developing organization and is subject to change.

There may be references in an OSAC Proposed Standard to other publications under

development by OSAC. The information in the Proposed Standard, and underlying concepts and

methodologies, may be used by the forensic‐science community before the completion of such

companion publications.

Any identification of commercial equipment, instruments, or materials in the Proposed Standard

is not a recommendation or endorsement by the U.S. Government and does not imply that the

equipment, instruments, or materials are necessarily the best available for the purpose.

To be placed on the OSAC Registry, certain types of standards receive a Scientific and Technical

Review (STR). The STR process is vital to OSAC’s mission of generating and recognizing

scientifically sound standards for producing and interpreting forensic science results. The STR

shall provide critical and knowledgeable reviews of draft standards to ensure that the published

methods that practitioners employ are scientifically valid, and the resulting claims are

trustworthy.

The STR consists of an independent and diverse panel, which may include subject matter experts,

human factors scientists, quality assurance personnel, and legal experts as applicable. The

selected group is tasked with evaluating the proposed standard based on a defined list of

scientific, administrative, and quality assurance based criteria.
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For more information about this important process, please visit our website

at: https://www.nist.gov/organization‐scientific‐area‐committees‐forensic‐science/scientific‐

technical‐review‐str‐process

   
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Standard Guide for Minimum Training Recommendations of Iris Image Examiners  

1. Scope

1.1 This standard provides minimum guidelines for facial image comparison documentation

and reporting.  

1.1.1 Documentation includes notes, images with markups and annotations, narratives,

worksheets, electronic records, investigative lead or forensic reports or any combination of

these.  

1.2 This standard does not discuss methods for how to conduct a facial image comparison,

opinion scales(s), or other requirements that may be agency specific.

2. Referenced Documents

2.1 ASTM Standards:

E3149 Standard Guide for Facial Image Comparison Feature List for Morphological Analysis

E1732 Standard Terminology Relating to Forensic Science  

2.2 Other Standard Documents

FISWG Physical Stability of Facial Features of Adults  

FISWG Guide for Role‐based Training in Facial Comparison

FISWG Standard Practice/Guide for Image Processing to Improve Automated Facial

Recognition Search Performance

FISWG Facial Comparison Overview and Methodology Guidelines

FISWG Glossary

OSAC Standard Framework for Developing Discipline Specific Methodology for ACE‐V

OSAC Standard Guide for Image Comparison Conclusions/Opinions
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3. Significance and Use

3.1 This standard provides the minimum requirements of information that shall be

documented in accordance with the type of report and agency specific procedures.  

3.2 This standard outlines the information needed to provide a contemporaneous record of

the analysis.  

4. Items to Include in a Facial Image Comparison

These items are not presented in order of importance or priority.

4.1 Administrative Data

4.1.1 Indication whether preliminary results,supplemental results, or amends an earlier

report

4.1.2 Case identifier

4.1.3 Dates

4.1.3.1 Date received

4.1.3.2 Date searched/compared

4.1.3.3 Date of image capture (if available)

4.1.4 Requestor(s) and contact information

4.1.5 Practitioner(s) name, title, and contact information

4.1.6 Details and scope of the request (if provided)

4.1.7 Filename/identifier of image received

4.1.8 Indication of whether a facial recognition (FR) search was conducted, and if

conducted, the results.  

4.1.8.1 Database searched

4.1.9 The original image submitted, or a visual example (e.g., still image from video

submitted), and the known (or candidate) image being compared.  
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4.2 Evaluation

4.2.1 Opinion scale used

4.2.2 Opinion reached including definitions or information and interpretation of what

drives an opinion (if applicable)

4.2.3 Disclaimer – Agencies should include in all facial image comparison reports their

own disclaimer identifying general limitations and the recommended usage of the report.  

4.2.4 Reference to Comparison Method used and any other tools, software or

technology utilized

4.2.5 Description of the disposition of any items requiring chain of custody.  

4.3 Verification

4.3.1 Verifier’s name, date, and result of verification

4.3.2 If no verification is completed, a disclaimer stating this shall be included

4.3.3 Printed name of technical reviewer

4.3.3.1 If no technical review of the report is made, indicate “none” or provide an

explanation as to why it was not done.  

4.3.4 Printed name, title, and signature of author or report and date of signature

4.3.5 Limitations of the method or databases (if used)

4.3.6 Disclosure of:

4.3.6.1 Absence of citable empirical measures of performance

4.3.6.2 If there were any deviations to the procedure, SOP, quality assurance procedures,

or from a published method.

4.3.6.3 If the agency is not accredited in the discipline or the procedure used is outside

the scope of accreditation, if applicable.  

4.3.7 Statement that makes it clear that the report does not contain all documentation

associated with the work performed (e.g., “Supporting documentation is maintained separate

from this report and is necessary for independent evaluation of the work, interpretation of the

data, and rendering of opinions.”)
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4.4 Comparison

4.4.1 Features of the face (as defined in the ASTM 3149) Facial image Comparison

Feature List for Morphological Analysis) visible in each known image used in a comparison

4.4.2 Representation of the images compared

5. Items to Retain as Part of the Case Record

5.1 In addition to the information above, the following shall also be saved:  

5.2 Analysis

5.2.1 Determination of suitability of image(s) for facial recognition search or facial

image comparison

5.2.2 Features of the face (as defined in the ASTM E3149 Facial Image Comparison

Feature List for Morphological Analysis) visible in each unknown image used in a comparison

5.2.3 Indicate whether images meet agency specific requirements for comparison (e.g.,

legal or procedural limitations to facial recognition searches.)

5.2.3.1 Explanation for determination that images do not meet specific requirements.

5.2.4 Processed image(s) (if applicable)

5.2.4.1 Filename/identifier of processed image(s)  (if applicable)

5.2.4.2 Steps taken to process images (e.g., cropping, rotating, adjusting exposure)

5.3 Comparison

5.3.1 Features of the face (as defined in ASTM E3149 Facial Image Comparison Feature

List for Morphological Analysis) visible in each known image used in a comparison  

5.4 Administrative Data

5.4.1 All correspondence (e.g., email, case notes, reports)

5.4.2 Relevant case information

5.4.3 Original received images
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5.4.4 Image Analysis Documentation, to include, but not limited to, factors such as

lighting conditions, image resolutions, obstructions, pose

5.4.5 Processed images

5.4.6 Chain of custofy

5.4.7 Disposition (if applicable)

5.4.8 Number of candidates returned (based on maximum number returned or

threshold used)

5.4.8.1 Rank order (number) of the potential candidate

5.4.9 Verifier’s notes and documentation (as per section 4.3)

6. Additional Information

6.1 The following shall be documented, as applicable:  

6.1.1 Algorithm

6.1.1.1 Name of Algorithm Vendor

6.1.1.2 Version

6.1.1.3 Specific configurations

6.1.1.4 Date implemented

6.1.2 Software

6.1.2.1 Vendor name

6.1.2.2 Version

6.1.2.3 Specific Configurations

6.1.2.4 Date implemented

6.2 Agency Accreditation or Quality Management System

6.2.1 Reference to agency comparison method

6.2.2 Reference to agency Standard Operating Procedures (SOP)

6.3 Practitioner Qualifications
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6.3.1 Training

6.3.2 Certification