Calibrating Your Car Camera: A Step-By-Step Guide

Calibrating your car camera is a critical process that ensures the camera is accurately aligned and able to detect objects and obstacles on the road. This process, known as ADAS (Advanced Driver Assistance Systems) camera calibration, is necessary for the proper functioning of safety features such as automatic emergency braking, lane departure warning, and adaptive cruise control. The calibration process involves physical alignment, configuring the components, and testing, and it must be performed by trained technicians using specialized tools and equipment. This paragraph will provide an introduction to the topic of car camera calibration, including its importance, the calibration process, and the benefits it offers to drivers.

Static Calibration

Prerequisites:

Firstly, gather all the materials required for the calibration process. This includes items such as calibration targets, an external camera, and any necessary tools or software.

Scene Setup:

The camera and target placements are crucial for effective calibration. Ensure that the cameras are rigidly mounted on the vehicle and will not be moved relative to the vehicle after the calibration process. The number and location of cameras will determine the scene setup. For example, a setup with 12 cameras mounted on a car roof would require a different arrangement than a setup with fewer cameras or cameras placed in different locations.

Capturing Data:

This step involves capturing both intrinsic and extrinsic data required for calibration. Intrinsic camera calibration focuses on the camera itself, while extrinsic camera calibration captures data from the vehicle's cameras and images captured with the external camera. Here are the detailed steps for each type of data capture:

Intrinsic Camera Calibration:

• Move a checkerboard pattern or AprilTag target in front of each camera requiring calibration.
• Start the recorder for all cameras and ensure it is properly configured.
• Move the checkerboard pattern from left to right in front of the camera, rotating it in all dimensions to calibrate pitch, roll, and yaw.
• Get closer and farther away from the camera to calibrate scale.
• Stop periodically to allow for motion-blur-free constraint detection.
• Capture at least 30 calibration images per camera.

Extrinsic Camera Calibration:

• Capture one image from each car camera using methods such as the DriveWorks Recorder, the DriveWorks Sample, or the DriveWorks Recorder Tool.
• Rename and copy the files to the appropriate locations as indicated by the calibration software.
• Additionally, capture a set of images with the external camera to construct a calibration graph. Ensure these images capture ground targets, wheel targets, and targets observed by individual cameras.
• Capture at least 20 images with the external camera, ensuring simultaneous observation of ground and wheel targets.

Using the Calibration Tools:

The calibration tools will take the captured data and generate camera calibration output. Follow the specific instructions provided by the calibration software suite to utilize the calibration tools effectively. This may include specifying directory structures, modifying target databases, and running calibration applications.

Validation:

Finally, validate the computed calibration by analyzing validation images. Compare the re-projections with the targets to ensure they are well-aligned. If there are misalignments, issues with intrinsic calibration, target corner detection, or target flatness may be the cause.

Dynamic Calibration

The dynamic calibration process typically takes up to one hour or more, depending on the vehicle's make and model. It begins with a technician connecting a diagnostic tool to identify which Advanced Driver Assistance Systems (ADAS) features are not in use, similar to static calibration. Then, the technician will drive the vehicle on roads with traffic and perform specific maneuvers. This process ensures that all safety features, such as lane departure warning, collision avoidance, and adaptive cruise control, operate correctly when needed.

After the dynamic calibration drive, a technician will verify the successful calibration through a test drive. This step ensures that the sensors and cameras are in perfect harmony and functioning correctly. Proper documentation of the calibration process is essential for transparency and future reference.

It is important to note that dynamic calibration may vary slightly depending on the vehicle's specific camera system and manufacturer requirements. Therefore, it is always recommended to refer to the vehicle manufacturer's guidelines or consult a trained technician for accurate instructions on dynamically calibrating a car camera.

After a collision

If your car has been in a collision, there's a chance that your ADAS (Advanced Driver Assistance Systems) camera may be damaged or out of calibration. This could affect the accuracy of the system, compromising your safety and that of other road users. Therefore, it is important to calibrate your car camera after a collision. Here are the steps you can follow:

Step 1: Check Your Insurance Coverage

Before performing any repairs or replacements, it is essential to understand your insurance coverage. In most cases, comprehensive coverage will include the cost of recalibrating your car camera after a collision, and you will only be responsible for paying the deductible. It is recommended to verify this with your insurance company and file a claim accordingly.

Step 2: Assess the Damage

Step 3: Replace the Camera if Necessary

If your car camera is damaged beyond repair, you will need to replace it. Consult a professional technician or your car dealer to source an appropriate replacement camera that is compatible with your vehicle's ADAS system. Ensure that the new camera meets the required specifications and is properly calibrated before installation.

Step 4: Prepare the Vehicle for Calibration

Park your vehicle on a level surface, ensuring that the ride height is controlled and level. Remove any heavy objects from the car, and check that the spare tire is in the correct place to maintain the proper weight and ride height. Ensure that your vehicle meets all the specific requirements for calibration, as outlined in your user manual or by the manufacturer.

Step 5: Perform the Calibration

The calibration process can be done in two ways: static calibration and dynamic calibration. Static calibration is performed in a controlled environment, using specialized tools and equipment to adjust the settings of your camera. Dynamic calibration, on the other hand, involves driving the vehicle under specific conditions to achieve optimal camera accuracy. Refer to your vehicle's manual or seek professional assistance to determine which type of calibration is required for your car.

Step 6: Verify the Calibration

Once the calibration process is complete, it is crucial to verify its success. Take your vehicle for a test drive and ensure that the sensors and cameras are functioning harmoniously. Check for any warning lights or error messages that may indicate a problem with the calibration. If you notice any issues, repeat the calibration process or seek professional assistance.

Step 7: Maintain Proper Documentation

After successfully calibrating your car camera, ensure that you maintain proper documentation. Record all the details of the calibration process, including adjustments, verification tests, and other relevant details. This documentation will help you keep a transparent maintenance history for future reference and ensure compliance with any manufacturer's guidelines or warranty requirements.

Wheel alignment

Primary Angles

The primary angles are the basic angle alignment of the wheels relative to each other and the car body. These adjustments are:

• Camber: the inward or outward angle of the tire when viewed from the front of the vehicle. Too much inward or outward tilt indicates improper alignment.
• Caster: the angle of the steering axis when viewed from the side of the vehicle. Positive caster means the steering axis tilts toward the driver, while negative caster means it tilts toward the front of the vehicle.
• Toe: the extent to which the tires turn inward or outward when viewed from above. Toe-in alignment is when the tires angle inward, while toe-out alignment is when they angle outward.

Secondary Angles

The secondary angles include numerous other adjustments, such as:

• Steering Axis Inclination (SAI)
• Track width difference
• Wheelbase difference
• Setback: the difference between right and left-side wheelbase length, which can also be measured as an angle.
• Rake: the difference between the front and rear ride heights, with a positive number indicating a larger rear ride height.

When to Get a Wheel Alignment

There are several signs that indicate your car needs a wheel alignment:

• Your vehicle pulls to one side
• Your steering wheel is off-centre when driving straight
• Steering wheel vibration
• Excessive tyre wear in certain spots

Camera replacement

There are a variety of replacement cameras available on the market, and they can be installed at the front or rear of a vehicle. When replacing a camera, it is important to ensure that it is compatible with your specific vehicle's make and model. The cost of a replacement camera can vary depending on its type, material, and dimensions, typically ranging from $100 to $250.

After replacing the camera, it is essential to calibrate it to ensure that all the ADAS (Advanced Driver Assistance Systems) safety systems work correctly. This includes functions such as lane departure warning, collision avoidance braking, and adaptive cruise control. The calibration process can be done statically, dynamically, or through a combination of both methods.

Static calibration is performed in a controlled environment by trained technicians who use specialized tools to adjust the hard-coded values of the camera, ensuring it is at the correct height and aligned with other sensors. Dynamic calibration, on the other hand, involves driving the vehicle and performing specific maneuvers to ensure that all safety features operate correctly when needed.

By replacing and properly calibrating your car camera, you can maintain the functionality of your vehicle's safety features and ensure a safer driving experience.

Frequently asked questions