Q&A

 

For a highly sophisticated functionality, such as the one demonstrated by Augmented Driving, all required technical components, both hard- and software, should be designed to provide the best performance. However, the iPhone is a mobile phone in the first place, not specifically designed for this kind of application.


So, some compromises regarding the final functionality had to be made due to the limited processing power and, even more important, the restrictions of the camera control. As a consequence, we made every effort trying to provide to you a unique and outstanding app by fully exploiting the great features of the iPhone 3GS. We very much hope that we have reached this goal.


For you to experience the best performance of Augmented Driving and to help you out in case of trouble, some interesting background information about the implemented functionality in form of this Q&A section is provided. 


Note: The Q&A section does not yet reflect the many changes of version 3.0!


Setup


Q: Where do I best mount the device?

A: The iPhone must be mounted at the windshield in landscape orientation close to the rear view mirror with the camera lens facing forward. Concerning the horizontal position, the camera lens should be mounted at the center of the windshield.


Q: At what height do I have to mount the device?

A: The higher the better. Augmented Driving supports mounting heights from 1.0m to 1.5m (about 3-5 feet). Please make sure to indicate the accurate height in the system settings panel. The height directly influences the system accuracy.


Q: What is the required orientation of the device?

A: The device must be mounted horizontally with minimum roll angle. Pitch and yaw angles are correctly set if, on a straight road, the vanishing point at the horizon and vehicles at some distance straight ahead are positioned within the HUD reticle.  


Q: Should I orient the device according to the pitch and roll indicators?

A: Since the iPhone‘s accelerometer is not perfectly calibrated the pitch and roll indicators are only intended to give you a rough estimate of orientation. Use the HUD reticle for exact orientation.


Q: Is there a video illustrating the correct setup process?

A: Yes, watch the quick installation video in the video section or directly start the video from the last help page in the Augmented Driving app on your iPhone. The video is also automatically played at the first three startups of Augmented Driving.



User interface


Q: How do I activate the options panel?

A: Tap the „OPT“ button in the HUD once to activate the option panels.


Q: How can I reach the quick manual pages?

A: In the option panels, tap the „i“ button to navigate to the quick manual pages.


Q: Which HUD modes are available and how can I activate them?

A: By tapping the „HUD“ button you toggle between different HUD modes, i.e. the full display mode, the HUD without augmentation overlays and the augmentation overlays only.


Q: How can I switch the units from m/s to mph or km/h?

A: Tap the speed indication in the upper left corner of the HUD to change units from m/s to km/h and mph. The display of the lane width in the lower center of the HUD is adjusted accordingly.


Q: How do I navigate between the different option or help pages?

A: Slide your finger up or down on the display. To go back (ESC) double tap on the screen. A help overlay will show you how to navigate between different panels.


Q: What does the number at the bottom center of the HUD mean?

A: If a lane is detected its width is displayed here in feet or meters depending on the units selected for the vehicle speed.


Q: Can I record a video of the scene on the display?

A: Currently, video recording is not yet supported. However, the system takes snapshots of the screen at different intervals and saves them to your photos. The standard interval is set to about 10 seconds. If one vehicle is tracked this interval is reduced to 5 seconds. If a vehicle is close ahead or more than one vehicle is tracked, a snapshot is taken every 2 seconds. When a snapshot is recorded „REC“ is displayed in the HUD. Recording is deactivated when the system is offline.


Q: How can I get rid of or change the system sounds?

A: You may adjust the system sounds in the sound options panel. You can either switch them off, select a sound or a spoken information message for different system events.



Calibration


Q: What is the auto-calibration for?

A: The auto-calibration feature enables fine-calibration of the yaw and pitch angles of your device to increase accuracy of vehicle distance and in-lane position estimation. For the auto-calibration to work the device must have been roughly calibrated, i.e. the correct camera height above ground must be indicated and the device should be properly oriented by means of the HUD reticle.


Q: What do the HUD messages "calib" and "ok" mean?

A: When „calib“ is displayed in the HUD the system is recalibrating the camera orientation. This usually occurs when you drive on a straight road with good lane markings. If the display says „ok“ you have a valid calibration with sufficient accuracy. If no status message is shown the system may be de-calibrated and is waiting for good conditions for auto-calibration. In general, the system is correctly calibrated after about 10 minutes of smooth straight driving with detected visible lane markings. 


Q: My calibration status says „failed“. What can I do?

A: Your device is not properly oriented. Tilt and rotate your iPhone until the HUD reticle correctly targets vehicles ahead. Then reset the calibration to its default values.


Q: How can I reset the calibration to its default values?

A: You can reset the auto-calibration values to their defaults by switching the auto-calibration off and on again in the system settings panel.


Q: How does a bad calibration affect the detection performance?

A: If your device is not properly installed or calibrated, you may not receive any detections at all, in the worst case. Please check height and orientation (use the HUD reticle) in this case. The accuracy of calibration can directly be observed by checking the lane-width and is also reflected by the accuracy of the lane change and vehicle ahead warnings.


Q: Are the calibration values stored on the device?

A: The calibration values are stored on the device with other parameters and are loaded the next time you use the system. Please consider that a new installation of the device in the car usually requires a new calibration. Eventually, you should reset the calibration values by switching the auto-calibration feature off and on again if you do not get valid detections.


Q: Which accuracy can I expect from the system?

A: In optimum conditions the accuracy is expected to be 10-15% for lane width, in-lane position and vehicle distance. However, due to the low frame-rate fast changes in the scene are only detected with a certain delay. Hence, the system is not suited for dynamic driving maneuvers. If your observed accuracy of the lane width is permanently significantly higher, you should re-check the mounting height and the orientation of your device.



Detection


Q: Why are they no detections?

A: Most likely the device is not installed or oriented correctly. Please check the camera height above ground in the system settings, enable auto-calibration and make sure that the HUD reticle is centered around the vanishing point at the horizon if you drive on a straight road.


Q: Why is the system use restricted to highways and country roads?

A: It is not really restricted. The system is designed to work best for straight and continuous lane-markings as they can be found on highways or main country roads. So, the system will operate on every road with these properties. Augmented Driving will definitely not give satisfactory results on small secondary streets or roads without good lane markings for the left and right lane boundaries. 


Q: Which kind of lane markings are detected?

A: The system has been tested with painted lane markings for the left and right lane boundaries. Less frequent other types of lane-markings (e.g. Botts‘ dots) may work as well, but have not yet been the focus of Augmented Driving. Additionally, the detection of lanes is restricted to a minimum width of 2m (7ft.) and a maximum width of 5m (16ft.).


Q: What about different lane markings for road works?

A: Augmented Driving does not yet exploit color information from the camera image. Thus, a clear distinction between regular lane markings and lane markings from road works cannot be made. Augmented Driving tries to identify the most plausible lane as a function of e.g. lane width, in-lane position and driver behavior.


Q: What kind of objects are detected?

A: Augmented Driving is designed to detect regular cars within the own lane. Certain types of vehicles may show a degraded detection performance depending on their size and shape. Motorcycles and bicycles are generally not detected by the system. In general, vehicle detection does not work at night. Please take into account that, at any time, you may encounter missed or wrong detections.


Q: Why does the vehicle detection not work without a visible lane?

A: In principle, the vehicle detection engine is able to detect and track all visible vehicles. For performance reasons on the iPhone we have restricted this to in-lane vehicles. Currently, in order to be able to assess the relevance of a detected vehicle with sufficient confidence, information about the own lane is required. This may be changed in a future release.


Q: What do the overlay colors green, yellow and red stand for?

A: New vehicles are only detected if they are driving in your lane. These vehicles are marked with a yellow overlay. When you approach them a „vehicle ahead“ message will be issued and the overlay color will be changed to red. If a vehicle leaves your lane or the lane is no longer tracked the overlay color changes to green. Please note that if no lane information is available, i.e. the vehicle overlay is green, no „vehicle ahead“ information will be issued. 


Q: When do I get a "leaving lane" message and can I influence its accuracy?

A: If a valid lane has been detected and the driver leaves this lane to the left or the right crossing one of the lane markings a message is issued to the driver. To precisely determine the time of line crossing, the system must be accurately calibrated and the width of the vehicle must be correctly indicated. You may slightly modify the true value of your vehicle width in the system settings to have an earlier or later warning. Please consider that the system may not react to dynamic lane changes.


Q: When do I get a "vehicle ahead" information and can I adjust this?

A: If you are closing in on a vehicle in your own lane a „vehicle ahead“ message is issued if the time-gap (time for you to reach the position of the vehicle ahead) is below the level indicated in the system settings. Please take into account that the system is not suited for highly dynamic situations and must not be used as a forward collision warning system or for driving situations with significant speed differences. Augmented Driving is intended to give you a hint when you should check your distance to the vehicle ahead while driving at comparable speed or while moving in a queue only. Please note that no „vehicle ahead“ information will be issued if lane information is not available, such as for vehicles marked by green overlays.



Operation conditions


Q: What about detection performance at daytime, nighttime and with glaring sunlight?

A: All imaging relevant properties are automatically set by the built-in camera and have not been optimized for the requirements of Augmented Driving. To cover operation in a wide range of illumination conditions, Augmented Driving has an internal image enhancement module. Nonetheless, the system works best during daytime with indirect sunlight and during dusk and dawn. In contrast to the lane detection, vehicles are generally not detected during nighttime. For extreme conditions with direct glaring sunlight, the overall detection performance may be strongly degraded.


Q: Why does the application need a valid GPS fix?

A: A valid GPS fix is required to obtain the ego-vehicle speed. This speed is used to calculate the time-gap between your car and a vehicle in front. Contingent on the current time-gap the “vehicle ahead” warning is triggered. If no or only weak GPS is available the message „offline - no GPS“ is displayed.


Q: Why does the application go to "offline" and I do not get any detections?

A: For functional reasons Augmented Driving becomes active above a minimum speed of about 24km/h or 15mph only. Below that speed or if the GPS signal is cut off (e.g. in a tunnel) the system goes offline, i.e. lane and vehicle detection, as well as the recording feature, are disabled. 


Q: Why, in the displayed image, is the sky so bright and the road so dark?

A: We are using the iPhone‘s camera API for Augmented Driving. Currently, this API functionality is very limited and does not allow to directly influence the behavior of the built-in camera. As of this, we cannot adapt shutter or gain properties of the camera to our application which makes the system sensitive to difficult lighting conditions (glaring sunlight etc.). All imaging relevant properties are automatically set by the built-in camera firmware.



Other


Q: Which frame-rate can be expected and what does it depend on?

A: Current frame-rates range from 6-11 frames per second depending on the analyzed scene and the HUD mode. The tracking of detected objects requires a good amount of processing power. A large portion of the processing power, however, is used for grabbing the camera image and a special processing for displaying the augmentation overlays. To have a higher performance of the overall system in terms of frame-rate, you may switch off these overlays by changing the HUD mode.


Q: How long can I have the system running without external power supply?

A: You should always use an external power supply when running Augmented Driving. Augmented Driving takes full usage of available system resources resulting in a high power consumption. Without external power supply the system will run for roughly 2-3 hours.


Q: Why does the camera switch off after a certain time?

A: If this occurs, simply tap the screen to reactivate the display. If the iPhone is locked you have to unlock the device to go back to the running application. Also, check the value of the time delay for locking your phone in the iPhone settings.


Q: Which improvements are planned for the future?

A: Current work is focusing on higher frame-rates and the robustness of the detection engines. Furthermore, detection in tunnels may be available in future versions, as well as detection of vehicles at night. If you have other special wishes of what to improve, please let us know.


Q: Where can I get additional support?

A: Check the video section for information on how to correctly setup the system. For further support, please contact us by email.



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