...
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).
...
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.
...
A 4’ wide FoV requires 1.2mm per foot of distance from subject; a 4½’ wide FoV requires 1.1mm per foot.
FoV | Distance from Object/Focal Length Needed for a Camera with 1/3” CCD | |||||
|---|---|---|---|---|---|---|
10' | 20' | 30' | 40' | 50' | 60' | |
4. | ||||||
...
0 ft.wide | 12mm | 24mm | 36mm | 48mm | 60mm | 72mm |
4.5 ft. wide | 11mm | 22mm | 33mm | 44mm | 55mm | 66mm |
The estimates on the previous page assume the use of 1/3” CCD (the most common size) camera format. Results will vary in applications using different size formats such as ½” or ¼”. Lens calculation tools are available from most camera manufacturers, (online and pocket ‘slide-rule’ versions).
...