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One standard metric used in describing video surveillance images is the Common Intermediate Format (CIF). This is a way to quickly
cite specific resolution levels that are commonly used in digital video. CIF specifies specific horizontal and vertical resolution levels.
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To explain further with an example, an image of a person recorded with 4CIF resolution may be able to be used by the 3VR system for facial analysis, however, the same image recorded at CIF resolution may not contain enough detail to be used for facial analysis unless the face is extremely large (at least a quarter of the width of the field of view). See “Camera Placement” on the following page for more information and examples on field of view for facial analysis.
Here is a quick video clip on Facial Surveillance Use Case in Banking
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Resolution | Megapixels | Width for Face (Feet) |
|---|---|---|
1024 X 768 | 0.7 | 6.5 |
1280 X 1024 | 1.3 | 8.0 |
1600 X 1200 | 2 | 10.5 |
2048 X 1536 | 3 | 13.5 |
The appearance of the field of view is obviously different with a width of 8.5’.
Pixels Between the Eyes
The same principles that apply to lower resolution cameras apply to megapixel cameras; 3VR still requires 35 pixels between the eyes. However, analysis is conducted on the full megapixel frame of the camera’s output. For example, with a resolution of 1280 x 1024, 3VR conducts facial analysis at 1280 x 1024 versus an analog camera at 4CIF (704 x 576).
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Digital images such as photographs and mugshots can be imported
CCTV cameras can be connected to a 3VR and video can be continuously analyzed
Best practices for each source differ significantly. Both sources are described and in Imported Images section below.
Imported Images
Any image that is in a supported digital format may be imported into the 3VR system. Supported formats include: BMP, JPEG and GIF. Only faces in images that meet the requirements enumerated in the previous two sections (pixels between the eyes, angles, lighting) may be successfully analyzed by the 3VR system.
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