SDW - Safe Distance Warning
Safe Distance Warning (SDW) feature is processing images directly on-device, without any cloud connectivity or additional add-ons.
SDW feature is part of outside camera features and is running at 4 FPS and at 2 FPS if inside camera AI features are turned on. The algorithm triggers an event called “SDW” when a specific vehicle speed/distance to the car in front report is reached. The event is uploaded on Cloud on cellular data by default.
SDW architecture of this feature consists of:
- A speed/accuracy optimized state of the art Convolution Neural Network (CNN) which is:
- detecting all the vehicles in the field of view;
- assessing vehicle types;
- assessing distance through the vehicle.
- A deep neural network which is processing the vehicles from the 1st CNN network and based on their characteristics
- type
- distance
- and an offset calibration parameter (distance from the camera to the center of the windshield) is assessing if a vehicle is in front of our car or in a side position (other lane).
- Knowing your car current speed (from GPS) and distance to the closest car in front:
- we can determine if you are keeping a safe distance to the car in front or not.
Very important!!!
In order to SDW to function properly, the position of the camera needs to be calibrated
- Calibration is made through Iris Fleet Manager where the client or the support staff will have to select if the camera is in the right side or the left side of the windshield
- also the distance from the middle vertical axis of the AI camera to the center of the mirror.
Note:
"Distance from center" is displayed as inch(s) or cm(s) depending on the user interface settings.
Settings
Default settings for vehicle speed/distance to the car in front report are in the table below, but every client can customize the thresholds depending on their needs by informing support which will make a request to engineering:
| Distance Class Category | Distance in m and feet | Speed threshold on your car for making an SDW event |
|---|---|---|
| Extremely close frontal vehicle | 0-3 m (0 feet -9 feet and 10) | 40 km / h (24.8 mph) |
| Close frontal vehicle | 3-6 m (9 feet and 10 - 19 feet and 8) | 70 km / h (43.5 mph) |
| Midrange frontal vehicle | 6-10 m (19 feet and 8- 32 feet and 9) | 85 km / h (52.8 mph) |
| Far-mid range frontal vehicle | 10-15 m (32 feet and 9 - 49 feet and 2) | 120 km / h (74.5 mph) |
| Far frontal vehicle | Over 15 m (over 49 feet and 2) | 140 km / h (87 mph) |
- Safe Distance warning accuracy is 96% during the day when the camera in mounted on the center of the car.
- On more than 10 cm offset from the center of the car the accuracy drops to 92%.
- During the night, the accuracy is 88% when the camera in mounted on the center of the car.
- On more than 10 cm offset from the center of the car the accuracy drops to 85%.
NOTE:
If false detections are present in a large quantity on a client, please inform engineering for adjusting the confidence thresholds.
Technical recommendation:
Mounting the camera as close to the center as possible will provide the highest Accuracy of this feature
Other information:
For safety, a positive detection will need to be validated on 2 consecutive frames in order to initiate a trigger.
- The vehicle will need to be between 0.5 - 1 seconds in a "Dangerous Zone" for an event to be triggered.