3vr P-Series SmartRecorder, Руководство по установке

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3VR SmartRecorder Installation and Configuration Guide
Image Use and Optimization for Facial
Analysis
Overview
3VR can analyze faces from two primary sources:
1. Digital images such as photographs and mugshots can be imported
2. 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 discussed 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.
Passport Photos / Mugshots
Generally, passport photos and mugshots provide high quality images for facial analysis. The angles and the light -
ing on these photos are generally within guidelines. Users should check that the pixels between the eyes are suf -
ficient. 3VR uses an import photo process that provides immediate feedback if the number of pixels between the
eyes are insufficient.
Images from DVRs
Images from DVRs may not provide sufficient quality for facial analysis. Users should qualify and set appropriate
expectations. Video from DVRs are often recorded at resolutions lower than 4CIF such as 2CIF or CIF. Because of
the reduction of resolution, the field of view needed for sufficient detail increase significantly. For example, images
at CIF resolution would need to have the face in focus in a field of view no wider than 2.25 feet.
Furthermore, the field of view of cameras on traditional DVRs is often 7’ to 12’ which is significantly greater than the
4.5 feet maximum field of view even if the video was recorded at 4CIF.
General Photos from Digital Cameras
Images from digital cameras may provide sufficient quality for facial analysis. To the extent that these photos ex -
hibit the same properties as passport photos, suitability will be more likely.
Photos of people in a group or performing an activity may not suitable if the person’s head is significantly tilted
horizontally or vertically. This is quite common and will affect performance.
Digital cameras provide megapixel images. Given the very high resolution of these images (compared to analog
photos), the width of the field of view may be very wide (as much as 20’ wide). Users should be careful to verify
that the image has not been reduced in resolution. This is a common technique to reduce the file size of an image.
However, if this is done it will significantly reduce proportionally the number of pixels between the eyes in faces in
the image.