Modern camera technology for safe driving: requirements & benefits

Camera technology for ADAS
Requirements for cameras in safe driver assistance systems

2024-11-27

Source:

Alexandra Müller-Plötz* | Translated by AI


5 min Reading Time

Whether it’s autonomous driving or advanced driver assistance systems: modern camera technology enables safe driving. The technical requirements placed on cameras.

Alexandra Müller-Plötz is Global Director Marketing at VIA optronics.

Cameras in cars play a crucial role in enhancing safety, functionality, and comfort in vehicles. As more ADAS (Advanced Driver Assistance Systems) and displays are integrated into vehicles, the camera technology within them becomes increasingly important. Additionally, legal regulations favor this growing importance: starting mid-2022, the EU mandates various driver assistance systems, such as rearview cameras, in new vehicles. This aligns with the USA, where this has been in place since 2018. Thus, cameras in cars are playing an ever-growing role.

Standard camera systems are used externally in the front and rear view areas, for 360° environment detection, and blind spot monitoring, performing various tasks such as lane keeping, emergency braking assistance, or traffic sign recognition. Internally, they serve as mirror replacements, in clusters (speedometers), navigation, driver and passenger monitoring, and entertainment systems.

The advantage of camera systems in vehicles

Depending on the vehicle’s design, forward visibility may be restricted, so front cameras assist in maneuvering, detecting obstacles, and parking. Rearview cameras cover a larger area behind the vehicle—especially when equipped with a wide-angle lens—than traditional rearview mirrors, minimizing the risk of touching people or objects in blind spots while reversing. Surround-view cameras process images from multiple cameras mounted around the vehicle to provide a complete 360-degree top-down view.

Digital side mirrors are increasingly being used, especially in electric vehicles and luxury models. A significantly reduced blind spot and a larger field of view increase safety in situations like lane changes or turning maneuvers. Depending on the area of use, cameras with different field-of-view sizes are offered—ranging from near to wide to ultra-wide. The elimination of mirrors reduces air resistance and energy consumption—a factor that is gaining increasing importance.

Requirements for the installed cameras

Since the generated information is often safety-relevant, high demands are placed on the camera technology and its functionality. To provide precise information for ADAS, cameras must have high resolution, high contrast, and high light sensitivity. For integration, they must also be as compact and—as particularly important in electric vehicles—as lightweight as possible. A wide operating temperature range from -40 bis 185 °F is also required. Good image quality must be maintained even with temperature fluctuations.

Optically, fine-tuning involves illumination strength, balancing human and machine vision, and correcting chromatic aberrations, as well as optimizing the wavelength, maximizing the field of view through distortion control, providing a uniform image without illumination drop-off across the field of view, and minimizing the deviation of the chief ray angle between the lens and sensor. When the camera captures reflections from the surroundings, it often results in blurred or shifted images, known as ghost images. Therefore, the technology used should be capable of minimizing these as much as possible.

Complex hardware and software in cameras

In the small cameras, there is now a tremendous amount of performance. Due to the many tasks and growing connectivity in the car, cameras are equipped with complex hardware and software. Different sensors can be used, such as CCD (Charge-Coupled Device) and CMOS (Complementary Metal-Oxide-Semiconductor), which have various properties regarding image quality, speed, and energy consumption.

Rugged housings protect the camera, especially in outdoor use, from environmental influences and mechanical damage. There are also various integration options, such as snap-in mechanisms or full installation. The tasks of the software are also diverse: image processing software is responsible for functions like facial recognition, environment and motion detection, and image analysis and enhancement. Control software manages features like exposure, contrast, and focus—usually via an HMI. Storage software handles the data transfer to the cloud and storage of images. Due to the many data processing tasks and extensive electronics in the car, power demand increases. Therefore, cameras should be designed to operate as energy-efficiently as possible.

E-mobility and what matters for cameras in vehicles

Like other vehicle components, cameras are subject to strict automotive-grade requirements due to their high functional demands. They must undergo extensive testing and qualification processes to ensure they can withstand the extreme conditions in the automotive sector. The required properties—corresponding, for example, to protection class IP69K—include robustness and durability, vibration and shock resistance, water and dust tightness, EMC compliance, and high-temperature resistance.

With the rise of electromobility, in addition to the usual criteria, additional requirements such as high voltage resistance, energy efficiency, effective heat dissipation, short circuit protection, and insulation resistance have come into focus to meet the specific challenges of these vehicles. To achieve the required robustness, the E-coating process is often used in the coating of cameras, similar to engine parts. In this process, a protective layer is applied to metallic surfaces using direct current. The paint particles adhere evenly to the surface and cure in the oven to form a resilient and attractive finish. The process is essential for industries such as the automotive sector and guarantees high-quality, robust, and uniform surfaces. The result is also a high resistance to corrosion, which is significant in humid or salty air conditions.

Validate cameras for the automotive industry

Given the long list of requirements, the validation of cameras for the automotive industry is a complex process that includes numerous tests such as hardware-in-the-loop simulation, end-of-line tests for correct calibration, and safety tests for failsafe functionality. In addition, behavior under heat, shock, chemical exposure, sunlight, or stray light is strictly tested. Finally, the cameras must be as easy as possible to integrate into the application.

Standard camera technology offers several advantages, such as low handling effort. Accessories like a selection of off-the-shelf lenses and sensors enable fast market launch and implementation, reducing the need for interfaces and validation, therefore lowering overall manufacturing costs. Interactive display systems provide seamless and comprehensive functionality, combining displays, camera technology, and central control elements into a cohesive overall solution.

Camera types with different optical requirements

The automotive market is undergoing a profound transformation—and development is progressing rapidly. Reliable and efficient camera technology is of crucial importance in this dynamic environment. As an established specialist, VIA optronics offers various types of cameras, whose optical design can be easily adapted to different optical requirements and other specific needs—with different fields of view and combinable with various sensors and lenses.

The systems are optimized for high and stable image quality, as well as good readability under changing light conditions, and meet all essential requirements for advanced technology. Great emphasis is placed on functional safety standards according to ISO 26262 in the design methodology and the selection of key components. Long-standing practical experience in mechanical, electrical, and optical design, along with a network of experienced partners, enables powerful, reliable, and market-ready applications swiftly. (heh)