Still Image Analysis
Still Image Authentication and Integrity Verification:
- Still image authentication is determining if a still image is an accurate and fair representation of whatever incident it purports to be or show
- A careful and thorough analysis of the video and its contents (what is seen in the image) can be used to confirm its authenticity and relevance to a case
- Integrity verification is an analysis to determine if an image has been changed or altered since it was originally recorded or exported or perhaps created or altered with AI
- Integrity verification can be done by analyzing an image’s metadata, by comparing hash values, and by looking for evidence of edits, alterations, or manipulations
An intruder was captured on surveillance video. Here we can see a forensic comparative analysis between the unknown shirt of the intruder (left) and a known shirt (right) recovered during the investigation of the incident. The matching details, circled in yellow, provides strong support that the unknown shirt is a match to the known shirt.
Still Image Enhancement and Clarification:
- We use a number of techniques and filters to clarify a still image to better see the details of what happened, who was involved, where people and objects are, and more
- Zooming and cropping: used to focus on a specific person or object and enlarge it to better see the details of who or what it is, or what is happening
- Lighting, color, and contrast corrections: by adjusting the luminance (lighting), colors, contrast, and more we can clarify a video and make details visible that may otherwise not be clear prior to enhancement
Several enhancement techniques were used to clarify this surveillance video including zooming, tracking, pausing, annotations (yellow arrow), luminance adjustments, trimming, and cropping. Such enhancements allow the viewer to better see what is happening, or perhaps what the subject is holding.
Photogrammetry:
- Photogrammetry is used to determine measurements of objects or space within an image
- Height analysis of a person can be determined by photogrammetry
- The size and dimensions of objects can be determined
- Distance between objects, such as vehicles, can be determined
- Reverse projection photogrammetry is a forensic process of determining whether an unknown object or person in a video is a size, height, or shape match to a known object or person
Photogrammetry:
- Photogrammetry is used to determine measurements of objects or space within a video or image
- Height analysis of a person can be determined by photogrammetry
- The size and dimensions of objects can be determined
- Distance between objects, such as vehicles, can be determined
- Laser Scans and LiDAR can be used to create a 3-Dimensional model of an area or object which can then be used to measure height, size, speed, distance, and more
- Reverse projection photogrammetry is a forensic process of determining whether an unknown object or person in a video is a size, height, or shape match to a known object or person
Using Laser Scanning technology and LiDAR, a 3-Dimensional model can be made of an area. This model can then be used to measure people, objects, distances, and more. This image is a LiDAR scan from the room where an intruder was captured on surveillance video. By placing elements of the surveillance video into the 3D model, we can determine the height of the unknown subject (the intruder).
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Have audio, video, or phone evidence that needs recovery, analysis, or clarification? Contact our lab to discuss your case with a forensic expert.