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Tips on Using Stream

Please see the suggestions below to get the most out of Stream. Refer to Stream FAQs for additional tips.

Stream Health ScoreA Stream Health Score under 0.75 indicates that Stream is not able to fully process the camera or video files for ALPR. To increase the Health Score, you can:

1) Set the eFPS based on the speed of the vehicles.
2) Run Stream on a stronger machine.
3) Decrease CPU utilization of other apps running on the machine.
4) Decrease camera resolution. This is not a huge-huge factor, but it does help.
Speed of ALPR ResultsStream sends the ALPR results (metadata and images) when vehicle plates are detected. To ensure the fastest way to forward ALPR results to your system or ParkPow, you can:

1) Set Max Prediction Delay to 1 second, rather than the default 6 seconds.
2) Make sure that Internet connectivity is fully available.
3) Send only the plate image (rather than vehicle image or original image) to your system. This is helpful if you’re sending ALPR results via a cellular modem.
4) Make sure that the Webhooks Receiver is fully functional.
ALPR AccuracyStream’s misreading of vehicle plates may be due to several factors.

1)If you are NOT able to see the vehicle plate well with your own eyes from the camera, then consider adjusting the camera zoom and/or position.
2) If the camera is shaky (e.g. inside a police car), then set Merge Buffer to 1 or 2 in the config file.
3) If an object (e.g. tree, large truck) often blocks the camera’s view of the target vehicle, consider adjusting the Max Prediction Delay to 0.5-1 second. This “forces” Stream to make a prediction faster.

If you are still facing accuracy issues, please send 3-5 images of incorrect reads via Contact Us.
Region/State AccuracyIt is a best practice to set the region parameter in Stream config. This is because (for example) a zero in one state/region is actually a letter O in another.

1) Identify the top 3-4 states/regions that are most common for a particular camera.
2) If possible, indicate specific states (e.g. us-az) rather than a general country (e.g. us).
3) Setting the specific states/regions simply optimizes Stream for these states/regions. If a vehicle from a totally unspecified region enters, Stream will still do a good job of detecting that vehicle’s plate and region.

If you are still facing accuracy issues, please send 3-5 images of incorrect reads via Contact Us.
Time-lapse VideosIf you are processing time-lapse videos using Stream, then

1) Set Sample Rate to 1 or 2 so that Stream can analyze every frame or every other frame.
2) Make sure to refer to our Guides on Stream Video Processing.