Axis Camera Down-Tilt Auto-Measurement
By Ethan Ace, Published Jan 06, 2015, 12:00am ESTTilting a camera too much can create problems.
Most commonly, it undermines getting clear shots of faces and license plates.
However, mounting angles are typically left up to guesswork, or trying to physically measure with plumb lines and protractors. Now, in their high end gyroscope-equipped models, Axis has added real-time tilt display to their cameras, allowing users to quickly measure and adjust their mounting angles.
In this note, we show how to use this feature and demonstrate its use on a camera in a video screencast.
Enabling Tilt Display
Beginning in firmware 5.55.3.4 tilt and rotation information may be overlayed on the camera's video stream in the Q1615, adding to its existing list of high-end features.
To display this information, users must turn on text overlay in the web interface of the camera, using the text "#op" for tilt and "#or" for rotation. Note that some VMSes may require the stream to be restarted (camera disabled and re-enabled) in order for this display to appear.
Finding Tilt
Once enabled, the camera will display the real-time tilt and rotation, seen below:
The way it is expressed can be confusing. Zero degrees for the Q1615 is vertical, aiming straight down, with 90 being level with the horizon. The tilt measurement shown in the OSD is degrees uptilt, not down. So for example, in order to aim a camera at 20 degrees downtilt, we need to subtract 20 from 90, so our tilt should display 70 in this case.
This video reviews tilt and rotation display in real time, as well as how to enable this feature:
Practical Applications
Though in many instances users may aim cameras simply by looking at the field of view on screen, this tilt display has practical uses in some applications. Some analytics systems such as LPR and facial recognition have strict angle of view requirements. Further, in some design specifications, consultants may specify specific downtilt figures. Using this on screen display is a simple way of assuring these requirements are met.
Finally, as we found in our Camera Height vs. Image Quality Test, to best capture facial details, cameras should be tilted no more than 15° below horizontal. Using Axis' tilt display is a quick way to find these mounting angles.
Limitations on Camera Availability
Though this is a neat tool, it is limited to Axis most expensive fixed camera series. This might be a sign of things to come for future cameras, for now most will not be able to use this.
