Concept
The Camera Monitor System (CMS), commonly referred to in the industry as the electronic rearview mirror, uses a combination of cameras and monitors to replace traditional optical rearview mirrors. In this display mode, external cameras capture images, which are then processed and displayed on in-cabin screens. It can also integrate features such as blind spot warnings and obstacle alerts, providing drivers with a comprehensive view of the surroundings. This effectively compensates for the limited field of view and blind spots of traditional rearview mirrors, enhancing driving safety and operational convenience.

Relevant Regulations
For safety reasons, all critical automotive components generally must pass mandatory certification before being installed in vehicles. To this end, automotive standardization organizations around the world have established various regulations for CMS. The most influential include UN-R46 issued by the United Nations Economic Commission for Europe, ISO 16505 published by the International Organization for Standardization, GB 15084 released by the Standardization Administration of China, and FMVSS 111 issued by the National Highway Traffic Safety Administration of the United States.

• ISO 16505：2019

Road vehicles — Ergonomic and performance aspects of Camera Monitor Systems — Requirements and test procedures.

• UNECE R46

Uniform provisions concerning the approval of devices for indirect vision and of motor vehicles with regard to the installation of these devices

• GB 15084-2022

Performance and installation requirements for indirect vision devices on motor vehicles

• FMVSS 111

LABORATORY TEST PROCEDURE FOR FMVSS 111 Rear Visibility (Other than School Buses)

Types of Mirrors
In the era of intelligent driving, CMS is gradually replacing traditional rearview mirrors. According to the GB 15084 standard, mirrors are mainly divided into seven categories: Class I interior rearview mirror, providing the driver with a rearward view inside the vehicle; Class II and Class III main exterior rearview mirrors, the familiar “left and right ears”; Class V blind-spot exterior mirror, further eliminating blind spots; Class IV wide-angle exterior rearview mirror, used to expand the field of view; Class VI front mirror, providing a forward view; and Class VII mirror for L-category vehicles with enclosed cabs.

Disadvantages of Traditional Mirrors
Although traditional rearview mirrors provide a basic field of view, they are based on the principle of physical mirror reflection and have three inherent defects that are difficult to overcome:

1. Blind spots (limited by mirror size and angle, posing safety hazards during lane changes and reversing);
2. High susceptibility to environmental conditions (rain causing blurred mirrors, and high-beam glare from following vehicles at night severely interfering with vision);
3. Increased aerodynamic drag (exterior rearview mirrors increase the drag coefficient, affecting fuel economy or the range of electric vehicles).

Traditional Rearview Mirror	Blind Spots
Blurred Mirror in Rain	Increased Drag Coefficient

Advantages of CMS
Addressing the pain points of traditional rearview mirrors, the CMS electronic rearview mirror achieves a comprehensive breakthrough through the digital combination of “external cameras + in-cabin monitors”. It not only revolutionizes the traditional way of acquiring the field of view but also integrates intelligent features such as blind spot warnings and obstacle alerts, upgrading the rearview mirror from a passive “reflector” to a proactive “safety partner”. The core advantages are as follows:
① Wider field of view and reduced blind spots
CMS captures images through multiple high-resolution cameras. After algorithmic stitching, it can present a 360° view without blind spots, and can actively eliminate blind spots through features like digital zoom and wide-angle adjustment.

② Stronger environmental adaptability, less susceptible to weather/lighting interference
CMS cameras are equipped with anti-fog and waterproof coatings, as well as automatic exposure adjustment functions. They can stably present clear images in extreme environments and varying lighting conditions, effectively overcoming the poor environmental adaptability of traditional rearview mirrors. ③ Reduced aerodynamic drag and improved energy efficiency
The cameras in CMS are much smaller than traditional rearview mirrors and can be integrated into the side of the vehicle body with a streamlined design. This significantly reduces the drag caused by airflow impact, thereby directly lowering vehicle driving energy consumption and improving energy efficiency. ④ Intelligent safety attributes
Unlike traditional rearview mirrors that only have the single function of passive reflection, CMS can be deeply integrated with the vehicle's ADAS, incorporating multiple active safety features such as Blind Spot Detection (BSD), Door Open Warning (DOW), and obstacle collision warnings.

CMS Testing Solutions
Yanding's automated CMS testing solution provides a one-stop solution, eliminating the tediousness and uncertainty of traditional manual testing.

Its core advantages are as follows:
(1) Automatic chart switching, convenient and labor-saving
(2) Programmable light source control to simulate complex lighting environments
(3) Automatic and precise movement with position memory to ensure test repeatability
(4) Automated analysis with RIQA software and one-click report generation

Supported Test Items: