Camera Axis Adjustment 101: Why Calibration Matters for Modern Vehicles
Modern vehicles are increasingly equipped with advanced camera systems that enable features like 360° surround view, lane departure warning, adaptive cruise control, and more. In order for these systems to function correctly, the cameras must be precisely aligned to the vehicle’s frame of reference. Even minor misalignments can cause significant errors in the camera’s perception of its surroundings.
Camera axis adjustment, also known as camera calibration, is the process of ensuring the cameras are mounted and aimed correctly so that the images they capture match up with the vehicle’s actual position and orientation. This is typically done by aligning the cameras to targets placed around the vehicle at known locations. The camera’s view of the targets is compared to the expected view based on the vehicle’s geometry, and adjustments are made as needed.
Proper camera axis adjustment is critical for the accuracy and reliability of camera-based driver assistance systems. Misaligned cameras can cause features like lane keeping assist or automatic emergency braking to activate at the wrong time or not at all. In the case of 360° camera systems, poor calibration can result in stitching errors that make obstacles appear closer or further away than they really are.
Camera calibration is not a one-time event. It needs to be checked and adjusted regularly, especially after any repairs or modifications that could alter the camera’s position. This includes windshield replacement, suspension work, and body repairs. Whenever a camera is removed and reinstalled, a full calibration procedure must be performed before the system can be used again. In this article, we’ll take a deep dive into the world of camera axis adjustment. We’ll cover why it’s important, when it’s needed, and how it’s performed on different types of camera systems. By the end, you’ll have a thorough understanding of this critical process and why it matters for the safety and functionality of today’s vehicles.
Types of Camera Systems
Before we get into the specifics of camera axis adjustment, it’s important to understand the different types of camera systems found on modern vehicles. While the exact configurations vary by make and model, most camera-based driver assistance features fall into one of a few main categories:
Forward Facing Cameras
Forward facing cameras are mounted at the top of the windshield, usually near the rear view mirror. They face directly forward and are used for features like lane departure warning, traffic sign recognition, and automatic high beams. These cameras typically have a relatively narrow field of view, around 50-60°, and a long range, up to 200 meters or more. They are designed to focus on distant objects directly in front of the vehicle.
Surround View Cameras
Surround view camera systems, also known as 360° cameras or bird’s eye view cameras, use multiple wide-angle cameras to create a top-down view of the vehicle’s surroundings. There are usually four cameras in total:
- Front camera mounted in the grille
- Rear camera mounted near the license plate
- Left side camera mounted under the side mirror
- Right side camera mounted under the side mirror
The images from these cameras are stitched together by software to create a seamless overhead view that looks like it was captured by a camera floating above the vehicle. This view is displayed on the infotainment screen and is used for low-speed maneuvering, such as parking. The side cameras typically have a field of view around 180° to capture as much of the vehicle’s side as possible. The front and rear cameras usually have a slightly narrower field of view, around 120-150°.
Rearview Cameras
Rearview cameras, also known as backup cameras, are mounted at the rear of the vehicle, usually near the license plate. They provide a wide-angle view behind the vehicle to assist with reversing and are required equipment on all new passenger vehicles sold in the United States as of May 2018. Rearview cameras typically have a field of view between 120-180° to capture as much of the area behind the vehicle as possible. They are designed to show a wide, close-up view to help the driver avoid obstacles while backing up.
Specialized Cameras
Some vehicles have additional cameras for specific purposes beyond the typical forward, surround, and rearview cameras. These might include:
- Trailer hitch cameras that provide a zoomed-in view of the hitch to aid with connecting a trailer
- Rearward facing cameras for rear cross traffic alert systems
- Mirror replacement cameras that take the place of traditional side mirrors
- Cameras integrated into the front bumper for tight maneuvering
The exact configuration of cameras varies widely by vehicle, but the calibration principles are similar for all types. Each camera must be aligned to a known reference frame so that the images it captures can be properly interpreted by the vehicle’s software.
When is Camera Axis Adjustment Needed?
Camera axis adjustment should be performed any time a camera is removed, replaced, or possibly knocked out of alignment. Some common situations that require camera calibration include:
Windshield Replacement
On most vehicles, the forward facing camera is mounted to the windshield near the rear view mirror. If the windshield is replaced, this camera will have to be removed and reinstalled. Even if it’s put back in the same position, there’s no guarantee it will be aligned exactly as it was before. Windshield replacement is one of the most common reasons for needing a forward facing camera calibration. Many automakers even specify that calibration must be performed after every windshield replacement, regardless of whether the camera appears to be aligned or not.
Suspension Work
Changes to the vehicle’s ride height or suspension geometry can alter the alignment of the cameras relative to the ground. This is especially true for surround view cameras, which are mounted low on the vehicle and have a wide field of view. Any significant suspension work, such as replacing shocks or springs, should be followed by a camera calibration to ensure the system is still accurate. Even a small change in ride height can have a big impact on the camera’s view of the world.
Body Repairs
Accidents that damage the front, rear, or sides of the vehicle where the cameras are mounted will obviously require calibration once the repairs are complete. However, even seemingly minor body work can necessitate a calibration if it involves removing or adjusting the camera mounting points. For example, replacing a front fender might require removing the side view camera. If the new fender isn’t exactly the same as the old one, the camera could end up in a slightly different position when it’s reinstalled. The only way to know for sure is to perform a calibration and check the alignment.
Camera Replacement
If a camera is damaged and needs to be replaced, the new one will have to be calibrated once it’s installed. Even if it’s an exact replacement part from the manufacturer, there’s no guarantee it will be mounted in precisely the same way as the old one. This is especially important for aftermarket camera additions. If a vehicle didn’t come from the factory with a certain camera system and one is added later, a full calibration is mandatory to ensure it’s aligned correctly.
Software Updates
In some cases, a camera calibration may be required after a software update, even if the cameras haven’t been physically disturbed. This is because the update may change how the vehicle interprets the images from the cameras. For example, an update to the surround view system software might alter the stitching algorithm that combines the images from the individual cameras. If the cameras aren’t calibrated to match this new algorithm, the resulting surround view image could be distorted or misaligned. Always check the release notes for any software updates to see if a camera calibration is recommended or required. When in doubt, it’s better to calibrate and make sure everything is aligned correctly.
Tools and Equipment for Camera Axis Adjustment
Performing a camera axis adjustment requires some specialized tools and a suitable work area. The exact equipment needed will vary by vehicle, but there are a few key items that are common to most calibration procedures:
Scan Tool
A scan tool, also known as a diagnostic tool or OBD tool, is a device that plugs into the vehicle’s OBD-II port and allows two-way communication with the vehicle’s systems. For camera calibration, the scan tool is used to put the cameras into calibration mode and check the alignment values. Most automakers have their own proprietary scan tools that are required for camera calibration on their vehicles. These include Ford’s IDS tool, GM’s GDS2 tool, Toyota’s Techstream tool, and so on. Aftermarket scan tools may also have camera calibration capabilities, but it’s important to verify that they support the specific make and model you’re working on.
Calibration Targets
Calibration targets are large patterned boards or mats that are placed around the vehicle at specific locations. The cameras use these targets as reference points to determine their alignment. The exact type and placement of the targets varies by vehicle and camera system. Common configurations include:
- A single large target placed in front of the vehicle for forward facing camera calibration
- Four smaller targets placed around the vehicle, one in front of each tire, for surround view camera calibration
- A target mounted on a stand behind the vehicle for rearview camera calibration
The targets usually have high-contrast patterns like checkerboards or QR codes that are easy for the cameras to identify. They may also have built-in leveling bubbles or adjustable feet to ensure they are perfectly flat and at the correct height. Using the correct targets and placing them accurately is critical for a successful calibration. Always refer to the manufacturer’s instructions for the specific targets and measurements to use for each vehicle.
Alignment Bay
Camera calibration must be performed indoors on a flat, level surface. An alignment bay or rack is ideal, as it provides a controlled environment with a perfectly level floor. If an alignment rack isn’t available, the next best option is a level concrete pad. The area should be large enough to position the vehicle and calibration targets with plenty of room to move around. Attempting to calibrate cameras outdoors or on an uneven surface will likely result in incorrect alignment. Wind and lighting changes can also interfere with the camera’s view of the targets. For the best results, always calibrate in a controlled indoor environment.
Measuring Equipment
In addition to the scan tool and targets, some basic measuring equipment is needed to set up for camera calibration:
- Tape measure for positioning the targets at the correct distances from the vehicle
- Plumb bob and string line for centering the targets laterally
- Wheel chocks for holding the vehicle in place during calibration
- Painter’s tape for marking target locations on the floor
- Laser level for checking target height and alignment (optional but helpful)
Having these tools on hand and knowing how to use them will make the calibration process go much more smoothly. Taking the time to set up the targets correctly is essential for getting accurate results.
Camera Calibration Procedures
The exact steps for calibrating a camera system vary by vehicle, but the general process is similar across most makes and models. Here’s a typical workflow for calibrating a forward facing camera:
- Drive the vehicle into the calibration area and center it in the space. Apply the parking brake and chock the wheels.
- Check that the tire pressures are set to the manufacturer’s specification. Even small differences in tire pressure can affect the vehicle’s ride height and throw off the camera alignment.
- Clean the camera lens and housing to ensure a clear view. Dirt, debris, or water droplets on the lens can interfere with the calibration.
- Connect the scan tool to the vehicle’s OBD-II port and navigate to the camera calibration menu. Select the option to calibrate the forward facing camera.
- Place the calibration target centered in front of the vehicle at the distance specified in the instructions, typically around 1-3 meters. Use the plumb bob and string line to ensure the target is directly in line with the center of the vehicle.
- Adjust the height of the target so that it is level with the camera. The exact height will be specified in the instructions and is usually close to the center of the windshield.
- Check that the target is facing directly towards the vehicle and is not tilted or skewed. Use the laser level to verify that it is perpendicular to the ground.
- On the scan tool, initiate the calibration process. The camera will take a series of images of the target and analyze them to determine its alignment.
- If the alignment is within the acceptable range, the scan tool will display a pass message. If not, it will give instructions for how to adjust the camera.
- If adjustments are needed, loosen the mounting bolts and carefully tilt the camera in small increments until the scan tool shows a passing alignment. Tighten the bolts and recheck.
- Once the calibration is complete, remove the target and clear any fault codes that may have been set during the process. Take the vehicle for a short test drive to verify the system is working correctly.
The process for calibrating other types of cameras is similar, but with different target placements and scan tool menus. For example, surround view camera calibration typically involves placing a target in front of each wheel and selecting the 360° camera option on the scan tool. Always refer to the manufacturer’s service information for the specific procedures, target locations, and tolerances for each vehicle. Attempting to calibrate a camera without the proper instructions is likely to result in incorrect alignment and system malfunctions.
Tips for Successful Camera Calibration
Calibrating cameras can seem intimidating at first, but it doesn’t have to be difficult if you follow a few key tips:
Read the Instructions
This may seem obvious, but it’s important enough to mention first. Always, always read through the entire calibration procedure before starting. Make sure you understand each step and have all the necessary tools and equipment on hand. Trying to figure it out as you go or substitute incorrect targets is a recipe for frustration and wasted time. Take a few minutes to familiarize yourself with the process upfront and your calibration will go much more smoothly.
Use the Right Tools
Using the correct scan tool and calibration targets for the vehicle you’re working on is essential. Aftermarket tools and generic targets may work in some cases, but they can also introduce errors that cause the calibration to fail. If you’re unsure whether a tool is compatible, check with the manufacturer or consult the service information. It’s better to take the time to get the right equipment than to waste time on a calibration that won’t work.
Set Up Carefully
Proper target placement is critical for accurate calibration. Double and triple check your measurements to ensure the targets are in the correct positions. If the instructions give a range of acceptable distances or heights, aim for the middle of the range. This gives you some wiggle room if the vehicle isn’t perfectly centered or the floor isn’t completely level. Use the plumb bob and laser level to verify that the targets are straight and true. Even a small amount of tilt can throw off the calibration.
Take Your Time
Camera calibration is not a race. Rushing through the process is more likely to result in mistakes that cause the calibration to fail. If something doesn’t look right or the scan tool gives an error message, stop and double check your setup. It’s much faster to get it right the first time than to have to start over because of a silly mistake.
Verify Your Work
After the calibration is complete, always take the vehicle for a test drive to ensure the system is working correctly. Pay attention to how the cameras perform in different situations, such as low light or rain. If you notice any errors or strange behavior, double check the calibration and redo it if necessary. It’s better to catch a problem now than to have a customer come back with a complaint later.
Conclusion
Camera axis adjustment is a critical part of servicing and maintaining modern vehicles equipped with advanced driver assistance systems. Properly aligned cameras are essential for the accuracy and reliability of features like lane keeping assist, adaptive cruise control, and surround view parking. As these systems become more common, the ability to calibrate cameras will be an increasingly important skill for technicians to have. Understanding the different types of camera systems, when calibration is needed, and how to perform the procedures correctly will be essential for working on the vehicles of today and tomorrow. By following the manufacturer’s instructions, using the correct tools, and taking the time to set up carefully, any technician can learn to calibrate cameras successfully. It may seem daunting at first, but with practice it will become just another routine part of the job. As vehicle technology continues to evolve, the methods for calibrating cameras may change, but the underlying principles will remain the same. Staying up to date on the latest procedures and equipment will be an ongoing challenge, but one that will pay off in satisfied customers and successful repairs. In the end, camera axis adjustment is all about ensuring that the vehicle’s perception of its surroundings matches reality. By taking the time to get it right, we can help keep drivers safe and make the most of the incredible technology in today’s vehicles.