Configuring License plate recognition (RR)

To configure License plate recognition (RR), do as follows:

1. Download Add-on RR LPR from the website and install it.

   Note

   To make the detection tool operate on Windows Server 2012 R2, make sure to install the Media Foundation component.

2. Create the License plate recognition (RR) object and select it. 
   
3. If you need to use this detection tool for real-time license plate recognition (comparison with the license plates lists), set the corresponding parameter to Yes (1) (see Configuring vehicle license plate recognition based on the created lists).
4. To record metadata to the database, select Yes from the Record objects tracking list (2).
5. If the camera supports multistreaming, select the stream for which detection is needed. Selecting a low-quality video stream reduces the load on the Server (3).
   

6. Select the Algorithm for detecting vehicle direction (4):

   1. By LP coordinates—if the license plate coordinates shift from top to bottom, then the vehicle is moving towards the camera; if the license plate coordinates shift from bottom to top, then the vehicle is moving away from the camera;

   2. By LP scale—if the license plate scale increases, then the vehicle is moving towards the camera; if it decreases, then the vehicle is moving away from the camera.

7. In the corresponding fields, select from the list one or more countries for LPR (5).
8. Select the processor for decoding video streams (6). When you select a GPU, a stand-alone graphics card takes priority (when decoding with NVIDIA NVDEC chips). If there is no appropriate GPU, the decoding will be done with Intel Quick Sync Video technology. Otherwise, the CPU resources will be used for decoding.
9. Set the number of frames processed per second by the detection tool (7). The value should be in the range [0,016; 100].
10. Set the minimum quality of LPR (8). The value should be in the range [0; 100]. The higher the minimum recognition quality, the fewer false detections will occur.

11. Select the processor for the detection tool: the CPU or one of NVIDIA GPUs (9) (see General information on configuring detection).
    

    Attention!

    It may take several minutes to launch the algorithm on NVIDIA GPU. You can use caching to speed up future launches (see Optimizing the operation of the License plate (RR) and RR vehicles recognition on GPU).

12. From the Speed detection list, select the unit of measurement of vehicle speed (10).
13. Specify the speed detection area height and width in meters (11, 12). The value should be in the range [0; 500].
14. If you need to search for the recognized LPs in the archive, set Yes for the corresponding parameter (13, see LPR search).

15. In the Event timeout field (14) specify the time interval in seconds between the initial LP recognition and event registration. The 0 value sets the event registration to the moment when the track disappears from FOV.
    

    Note

    Skip this step with License plate recognition - Search in archive (RR).

    

16. By default, the analyzed frames are scaled down to a specified resolution (15, 1920 pixels on the longer side). This is how it works:

    1. If the longer side of the source image exceeds the value specified in the Frame size change field, it is divided by two.

    2. If the resulting resolution falls below the specified value, this resolution will be used further.

    3. If the resulting resolution still exceeds the specified value, it is divided by two, etc.

       Note

       For example, the source image resolution is 2048*1536, and the specified value is set to 1000.

       In this case, the source resolution will be halved two times (512*384), as after the first division, the number of pixels on the longer side exceeds the limit (1024 > 1000).

       If detection is performed on a higher resolution stream and detection errors occur, it is recommended to reduce the compression.

17. Specify the maximum number of recognition threads (16). If the value is 0, the recognition process will occur in the same thread that starts it.
    

    Attention!

    The cumulative value of this parameters across all LPR detection tools should not exceed the number of CPU cores and is limited to 100.

    Attention!

    Starting with DetectorPack 3.8.0.95 the Maximum number of threads parameter is not present.

18. You can configure the LPR area in the preview window. The area is resized by moving the anchor points . 
    

    Note

     For your convenience, you can click the button and configure the mask on a still frame. To undo, click this button again.

    Detection zone is displayed by default. You can click the button to hide the area. To undo, click this button again.

19. Click the Apply button.

Configuration of License plate recognition (RR) is now complete.