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| Note | ||
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The detection tool will not operate on the Server with a different MAC address.
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Restart the Server (see Shutting down a Server, Starting a Server).
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For the License plate recognition IV to work, you must activate the license (see Activating the license for the License plate recognition IV in Windows OS, Activating the license for the License plate recognition IV in Linux OS). |
To configure the License plate recognition IV detector, do the following:
- Go to the Detectors tab.
- Below the required camera, click Create… → Category: Vehicle → License plate recognition IV.
By default, the detector is enabled and set to recognize vehicle license plates.
If necessary, you can change the detector parameters. The list of parameters is given in the table:
| Parameter | Value | Description |
|---|---|---|
| Object features | ||
| Check in lists | Yes | The parameter is disabled by default. If you want to use this detector to check in lists of vehicle license plates, select the Yes value (see Checking in lists of LPs) |
| No | ||
| Record objects tracking | Yes | The metadata of the video stream is recorded to the database by default. To disable the parameter, select the No value |
| No | ||
| Video stream | Main stream | |
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| If the camera supports multistreaming, select the stream for which detection is needed |
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| . Selecting a low-quality video stream |
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| reduces the load on the |
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Select the Algorithm for detecting vehicle direction (1):
- By LP coordinates: if LP coordinates change position from top to bottom, the vehicle moves towards the camera. If LP coordinates change position from bottom to top, the vehicle moves away from the camera.
- By LP scale change: if LP scale increases, the vehicle moves towards the camera. If LP scale decreases, the vehicle moves away from the camera.
Select the country from the list for LPR and the level of recognition accuracy (2).
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High CPU load, high recognition accuracy—provides the maximum recognition accuracy, but creates a high load on the CPU and/or GPU.
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Medium CPU load, medium recognition accuracy—provides a high recognition accuracy, requires less computing resources than the maximum accuracy.
| server | ||
| Second stream | ||
| Other | ||
| Enable | Yes | The detector is enabled by default. To disable the detector, select the No value |
| No | ||
| Name | License plate recognition IV | Enter the detector name or leave the default name |
| Decoder mode | Auto | |
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| Select a processing resource for decoding video streams |
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| . When you select a GPU, a stand-alone graphics card takes priority (when decoding with |
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| Nvidia NVDEC chips). If there is no appropriate GPU, the decoding will use the Intel Quick Sync Video technology. Otherwise, CPU resources will be used for decoding |
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| CPU | ||
| GPU | ||
| HuaweiNPU | ||
| Type | License plate recognition IV | Name of the detector type (non-editable field) |
| Advanced settings | ||
| Frame size change | 1920 | The analyzed frames |
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are scaled down to a specified resolution ( |
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1920 pixels on the longer side) by default. |
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The following algorithm is used:
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| Initiate event in (sec) | 1 | Specify the time in seconds after which an event must be generated after recognizing a license plate in the frame. The value must be in the range [0, |
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| 3600]. If the value is 0, an event will be generated after the track with a license plate is lost | ||
| Maximal number of characters in LP | 10 | Specify |
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| the maximum number of |
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| characters in the license plate. The |
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| value must be in the range [ |
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| 1 |
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| , 20] | ||
| Minimal number of characters in LP | 5 | Specify the minimum number of characters in the license plate. The value must |
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| be in the range [1 |
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| , 20] | ||
| Minimum recognition quality, in % | 80 | Specify the minimum quality of license plates recognition as a percentage |
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| . The higher the minimum recognition quality, the fewer false |
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| events. The value |
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| must be in the range [0 |
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| , 100] |
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| Note | ||
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It may take several minutes to launch the algorithm on NVIDIA GPU. If there are several GPUs in the system, a specific NVIDIA GPU value can be assigned to each License plate recognition (IV) tool. |
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| Track retention time (sec) | 3 | Specify the time |
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in seconds after which the vehicle track is considered lost. |
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The value |
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must be in the range [0 |
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, 3600].
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| Basic settings | |||||||
| Algorithm for detecting vehicle direction | By LP coordinates | The By LP coordinates algorithm is used by default. It works as follows: if the coordinates of the vehicle license plate shift from top to bottom (the vehicle moves towards the camera) and if the coordinates of the vehicle license plate shift from bottom to top (the vehicle moves away from the camera). | |||||
| By LP scale change | |||||||
| Maximum LP width | 10 | Specify the maximum and minimum width of the license plate as a percentage according to the actual size of the license plate in the frame. The value must be in the range [0, 100].
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| Minimum LP width | 1 | ||||||
| Processing unit | CPU | Select a processor for the detector operation (see Selecting Nvidia GPU when configuring detectors).
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| Nvidia GPU 0 | |||||||
| Nvidia GPU 1 | |||||||
| Nvidia GPU 2 | |||||||
| Nvidia GPU 3 | |||||||
| Country selection | |||||||
| Country name |
| Select from the list the country whose license plates you want to recognize and select the recognition accuracy:
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In the window, specify the area in which license plate detection and recognition will be performed. You can adjust the area by moving the anchor points 
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| Info | ||
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To save the parameters of the detector, click the Apply 
button. To cancel the changes, click the Cancel 
button.
Configuration of the License plate recognition IV is complete. If necessary, you can create and configure the necessary sub-detectors on the basis of the License plate recognition IV (IV) is now completesee Standard sub-detectors).
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