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Image requirements for the Motion detector and its sub-detectors

Requirements for the operation of the Motion detector and its sub-detectors are given in the table:

Camera
  • Camera shake must not result in image offsets greater

Motion detection runs properly if video match the following requirements:

...

  • than 1% of the frame size

...

Lighting

...

  • Moderate lighting.

...

  • In conditions of insufficient (night) or

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  • excessive lighting (light-striking), the quality of

...

  • analytics

...

  • performance can decrease
  • No

...

  • abrupt changes in lighting

...

Scene and camera angle

...

  • Moving objects

...

  • are visually separable from each other

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  • The background

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  • is mostly static and doesn't change abruptly
  • Moving objects are minimally obscured by static objects in the scene

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  • (columns, trees,

...

  • and so on)

  • Analytics can work incorrectly if:

    • the analyzed scene have reflective surfaces and sharp shadows from moving objects

    • there are extended monochromatic objects in the frame

Some requirements depend on whether you use the Motion detector only or its sub-detectors (see Standard sub-detectors). The

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  1. There is no noise on the video image and there are no artifacts caused by the compression algorithm.
  2. The speed of objects in the frame must be at least 1 pixel per second.

  3. In order to detect the object it is to be visible at not less than 8 frames.

  4. Within two adjacent frames the object cannot move in the movement direction for the distance that is longer than its size. This condition is essential for correct calculation of the object’s trajectory (track).

Some requirements depend on whether only a video motion detection will be used, or VMD-based scene analytics detection tools will be used as well. The difference in requirements is shown in the table:

Requirements
VMDVMD-based scene analytics detection tools
Motion detectorMotion detector sub-detectors

Resolution in pixels

Not less than
At least 320х240
Not less than
At least 640х360
FPS
Not less than
At least 1
Not less than
At least 6

Image

Scene analytics

Work with image

Analytics only works with color images
Scene analytics
Analytics works with both gray and color images

Size of objects in the image

The width and height of the objects in the image must be not less than 1% of the frame size (if resolution is over 704x576 pixels) or 15 pixels for lower resolution

The width or height of the objects in the image must be not less than 1% of the frame size (if resolution is over 1920x1080 pixels) or 15 pixels for lower resolution

Size of objects in the image relative to the frame size

The width and height of the objects in the image must not exceed 75% of the frame size

The width or height of the objects in the image must not exceed 75% of the frame size