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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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Camera Face Requirement Chart in 3VR
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Face Size | 35 pixels between the eyes required. Rules of Thumb: The field of view when subject is in focus must be less than 4.5 feet ot the face, or the face width must be at least 1/7 of the field of view. |
Zoom | Zoom lens recommended: 5-50 mm (5%-15%) angle of view. |
Vertical Slope | Recommended 20% slope from eye level. (see example), rule of thumb: The middle of the nose should be higher or at least the same level as the bottom of the earlobes. |
Horizontal Angle: | Thumb Rule: The image must simultaneously show both ears of the subject. |
Lighting | High quality required with wide dynamic range. Well lit, no harsh shadows or glare |
Event Length | There must be a period of time during which the subject is in focus, large enough (face 1/7 of the field of view), well lit, facing the camera so that both ears are visible, and the middle of the nose is above the bottom of the earlobes. Recommended: 3 seconds, (minimum 2 seconds) |
Camera Features | B/W or Color (appropriate to lighting conditions). Back light control sometime helpful. Manual or Auto-iris lens(as appropriate to the application) |
Examples | Doorways, Hallways, Entrances, Exits Queue lines Teller lines |
Result
Quality Image
With better understanding on optimization of image quality you can now determine:
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