Perfect pixel count

The Axis pixel counter

You can now validate your established operational requirements.

Axis pixel counter allows you to validate the operational requirements with the click of a button when setting up the camera. The pixel counter is a visual rectangular aid that displays in the camera’s live view, with a corresponding counter to show the box’s width and height. This can be adjusted and moved around the image with drag-and-drop.

Figure 2: Use an object of a known size in the scene, for easier calculations. The door opening here measures approximately 100cm, so 500 pixels gives enough resolution for identification.

A pixel counter example

A store owner wishes to monitor the checkout counter. The operational requirement is for identification, and another is to see as much of the store as possible. To fulfill these requirements using a 720p dome camera, the pixel counter can be set to 500 pixels, and the camera adjusted so that a 1 m ruler fits inside the pixel counter. Finally, the camera can be redirected to ensure the best possible view of the store, thereby fulfilling both requests.

This could also be done by using any other object of a known size, such as an A4 sheet of paper (30 cm wide) or a door, as shown above. For identification purposes, the pixel size for an A4 sheet would be 5 px/cm multiplied by 30 = 150 pixels.

This method can also be used to figure out distances at which a camera can provide an adequate image – i.e. how far a camera can “see”.

Conclusion