Hikvision LPR - Image Logs
The Hikvision LPR - image logs plugin stores in ACCELERO the plate images captured by Hikvision LPR devices (vehicle license plate recognition) and provides a screen to search those photos. Each capture is kept with the plate read, the recognition quality, the source device, and the date/time.
This feature is provided as a plugin (hikvision_lpr_picturesaver) and must be installed and enabled by the IONGRADE technical team. Contact support to check compatibility with your ACCELERO version.
Current plugin version: 0.0.5 — compatible with ACCELERO 2.16.4 or higher.
The plugin works on top of the Hikvision LPR devices already registered in ACCELERO. See Hikvision Integration for registering the equipment.
What the plugin does
| Feature | What happens in ACCELERO |
|---|---|
| LPR photo storage | The images sent by the Hikvision LPR devices are received via MQTT and written to disk on the server, along with the plate, quality, and date/time |
| Photo search | A dedicated screen (Hikvision LPR Photos) allows filtering the captures by date, device, and plate, displaying the image |
| Quota control | A storage quota (in MB) is defined; the system tracks the current usage |
| Automatic cleanup (FIFO) | When the quota is reached, the oldest images are removed automatically with each new capture |
| Manual cleanup | A button on the configuration screen runs the storage cleanup on demand |
| Photo deletion | Individual or batch deletion from the search screen, removing the record and the image file |
It keeps a searchable history of the plates captured by the Hikvision LPR cameras, with disk space control to prevent unlimited storage growth.
Enabling storage per device
Photo sending is configured on each Hikvision LPR device. In the device edit screen, the plugin adds the field:
| Field | Description |
|---|---|
| Store LPR photos | On/off switch. When enabled, the images captured by that device are forwarded and stored in ACCELERO |
Edit screen of the Hikvision LPR device with the Store LPR photos switch added by the plugin.
Only devices with Store LPR photos enabled forward images for storage. Devices with the switch off continue operating normally in access control, but their captures are not kept by this plugin.
Configuration
Navigation path: Settings > Integrations - Hikvision - LPR Photos
The configuration screen has a single tab, General.
General tab of the Settings > Integrations - Hikvision - LPR Photos screen, showing the Storage quota and Storage quota (usage) fields and the Run cleanup now button.
| Field | Description |
|---|---|
| Storage quota | Storage limit for the photos, in MB. Required field. Default value on installation: 10 |
| Storage quota (usage) | Space currently occupied by the stored images (read-only) |
Screen buttons
| Button | Function |
|---|---|
| Run cleanup now | Runs the storage cleanup on demand, removing the oldest images until the quota is respected. Requires confirmation |
| Save | Persists the configured storage quota |
| Back | Returns to the settings list |
Run cleanup now deletes image files from the disk. The action is recorded in the system audit log with the number of deleted files.
Hikvision LPR Photos Screen
Path: side menu > Settings > Hikvision LPR Photos
Lists all stored captures, with search filters and image viewing.
Hikvision LPR Photos screen showing the list with the columns (date/time, device, quality, plate, photo) and the search panel open.
Search filters
| Filter | Description |
|---|---|
| Start date / End date | Selection by capture date/time |
| Hikvision LPR device | Multi-selection of the source LPR devices |
| Plate | Text search by the plate read |
Columns
| Column | Content |
|---|---|
| Date/time | Moment of the capture (default sorting: most recent first) |
| Hikvision LPR device | Device that generated the capture (N/A when not identified) |
| Quality | Recognition confidence index reported by the camera |
| Plate | Plate read by the device |
| Photo | Thumbnail of the captured image |
Actions
| Action | Function |
|---|---|
| Delete (row / selection) | Removes the selected records and their image files. Available in batch via the More actions > Delete menu |
How the photos reach ACCELERO
The Hikvision LPR device publishes each capture to an MQTT topic (.../hikvision/lpr/<device>/photoforward). The plugin listens to this topic and, for each message, expects the fields:
| Message field | Goes to |
|---|---|
timestamp | Capture date/time |
licenseplate | Plate |
confidence | Quality (confidence) |
photo | Plate image (base64-encoded) |
The plugin writes the record to the database and saves the image as a .jpg file on the server. Then, it runs the storage cleanup routine to keep usage within the quota.
If the received message does not carry a device, date/time, plate, quality, or image, the capture is ignored and the reason is recorded in the plugin's debug log.
Cleanup and space control
The plugin keeps disk usage within the configured Storage quota through a FIFO strategy (the oldest images are the first to be removed):
- Automatic: with each new photo received, the plugin checks the usage and, if the quota is exceeded, removes the oldest images until returning to the limit.
- Manual: the Run cleanup now button, on the configuration screen, triggers the same routine on demand.
LPR images can accumulate quickly in high-traffic environments. Set the Storage quota considering the daily capture volume and the history period you need to keep searchable.
Permissions
The plugin creates dedicated permissions, assignable to the operator Profiles:
| Permission | What it grants |
|---|---|
| Hikvision - monitor LPR photos | Access and search the Hikvision LPR Photos screen |
| Hikvision - delete LPR photos | Delete photos (individual or batch) |
| Hikvision - Clear LPR photos | Run the storage cleanup |
Use cases
Enable LPR photo storage
- Request the installation of the
hikvision_lpr_picturesaverplugin from IONGRADE. - On each desired Hikvision LPR device, enable the Store LPR photos switch and save.
- In
Settings > Integrations - Hikvision - LPR Photos, set the Storage quota (MB) and save. - Assign the monitoring permissions to the operator profiles that should consult the photos.
- Track the Hikvision LPR Photos screen to confirm that the captures are arriving.
Search for the photo of a plate
- Access Hikvision LPR Photos.
- Open the search and enter the Plate and/or the Start date / End date range.
- Optionally filter by the Hikvision LPR device.
- View the image in the Photo column.
Free up disk space
- Check the Storage quota (usage) field on the configuration screen.
- If necessary, adjust the Storage quota and save.
- Click Run cleanup now and confirm to remove the excess oldest images.
Best practices
- Enable only where necessary: enable Store LPR photos only on the devices whose captures you really need to keep, avoiding filling the disk with irrelevant images.
- Quota compatible with the disk: set the quota within the available space on the ACCELERO server, with a safety margin.
- Restricted permissions: grant Hikvision - delete LPR photos and Hikvision - Clear LPR photos only to trusted operators, since both remove data permanently.
Troubleshooting
Photos do not appear in the list
Possible causes:
- The Store LPR photos switch is disabled on the device
- The device is not publishing the captures via MQTT
- Messages arriving incomplete (without a plate, image, etc.)
Solution:
- Confirm that Store LPR photos is enabled in the device edit screen.
- Check the MQTT communication between the device and ACCELERO.
- If it persists, contact IONGRADE support with the device reference.
Image does not load (photo unavailable)
Possible causes:
- The image file was removed by the cleanup routine or by deletion
- The record exists, but the
.jpgfile is no longer on the disk
Solution:
- When the file is not found, the system displays a default "no photo" image. Old captures may have been removed by the FIFO cleanup when the quota was reached.
Storage usage always high
Possible causes:
- Storage quota undersized for the capture volume
- Too many devices with Store LPR photos enabled
Solution:
- Reassess the Storage quota on the configuration screen.
- Disable storage on the devices that do not require an image history.
- Use Run cleanup now to free up space immediately.
Integration with other modules
Hikvision Devices
The plugin extends the Hikvision LPR devices with the Store LPR photos switch. See Hikvision Integration for registering and operating this equipment.
Profiles and Operators
Access to the plugin's screens and actions is controlled by the permissions assigned to the Profiles of the Operators.
Vehicles
The captures record the plate read by the cameras, which can support the verification of vehicle accesses managed in Vehicles.
Next Steps
- Hikvision Integration — Registration and operation of the Hikvision LPR devices
- Profiles — Configure the access permissions to the LPR photos
- Vehicles — Registration of vehicles and plates in ACCELERO
- Plugins — Learn more about ACCELERO's plugin system