Illumination Control Modes in Endoscope Camera Module: Technical Principles and Comparative Analysis

Endoscopic camera modules are core components of medical endoscopic systems, and their dimming performance directly affects the clarity of surgical images, the accuracy of lesion identification, and the safety of minimally invasive procedures. With the continuous advancement of medical imaging technology, multiple dimming modes have been developed for endoscopic camera modules to adapt to complex clinical scenarios such as different tissue depths, cavity sizes, and surgical lighting environments. This article will systematically sort out the main dimming modes of endoscopic camera modules, and conduct an in-depth analysis of their advantages, disadvantages and applicable scenarios.

Based on technical principles and application characteristics, the dimming modes of endoscopic camera modules can be divided into four main categories: manual dimming, automatic dimming, adaptive fusion dimming, and local dimming. Each mode has unique working mechanisms and design priorities, aiming to meet the diverse needs of clinical diagnosis and treatment.

Manual dimming is the most basic dimming mode, which relies on the operator to manually adjust the brightness level of the endoscopic light source according to the observed image effect. This mode is usually equipped with multi-level adjustable gears, and the common adjustment range is 1-19 levels, which can be subdivided into more precise gears (such as 133 gears) to realize fine brightness control . The adjustment operation is generally completed through the physical buttons on the endoscope handle or the touch panel of the host, and the operator can set the fixed brightness according to the specific surgical site and tissue characteristics.

Automatic dimming realizes intelligent brightness adjustment through the closed-loop feedback mechanism of the image sensor and the light source controller. The system continuously collects the image signal captured by the endoscope camera, analyzes the average brightness, contrast and other parameters of the image in real time, and automatically adjusts the output power of the LED light source to maintain the stability of the image brightness . This mode does not require manual intervention, and can quickly adapt to changes in the lighting environment, such as the transition from a small cavity to a large cavity during endoscopic examination.

As an innovative dimming technology, adaptive fusion dimming is based on multi-core heterogeneous hardware platforms and artificial intelligence algorithms . It not only has the basic function of automatic brightness adjustment, but also can realize real-time perception of illumination depth and regional brightness differences. For complex clinical scenarios (such as observing the gastric cavity), it can match the optimal dimming strategy and image brightness processing algorithm, and simultaneously ensure the brightness and clarity of the near and far scenes in the observation area . This mode solves the problem that traditional automatic dimming is difficult to balance the brightness of different areas, and further improves the quality of endoscopic images.

Local dimming is a dimming mode oriented to high-definition imaging. It divides the light source emission area into multiple independent control units, and adjusts the brightness of different areas according to the image details . By enhancing the brightness of the target area and reducing the brightness of the non-target area, it can significantly improve the contrast and color gamut of the image, making the lesion area more prominent . This mode is often used in 4K ultra-high-definition endoscopic systems to meet the needs of precise diagnosis of early tumors.

Advantages: The brightness adjustment is precise and controllable, and the fixed brightness can be set according to the operator's experience and surgical needs, avoiding the image fluctuation caused by automatic adjustment. It has low technical requirements for equipment, simple structure and low cost, and is widely used in basic endoscopic equipment.

Disadvantages: It relies heavily on the operator's experience. Improper adjustment may lead to over-bright or over-dark images, which affect the judgment of lesions. During the operation, manual adjustment will distract the operator's attention and reduce the efficiency of the operation. It cannot adapt to the dynamic changes of the lighting environment in real time, and there is a lag in brightness adjustment.

Advantages: It can automatically adapt to the changes of the surgical environment, maintain the stability of the image brightness, reduce the operation burden of the operator, and improve the efficiency of diagnosis and treatment. It has strong adaptability to general clinical scenarios (such as intestinal cavity examination), and can avoid the missed diagnosis caused by improper manual adjustment. The operation threshold is low, and new operators can quickly get started .

Disadvantages: In complex scenes with large differences in near and far brightness (such as the gastric cavity), it is difficult to balance the brightness of all areas, and there may be phenomena such as overexposure of the near scene or underexposure of the far scene . The adjustment strategy is relatively fixed, and it is difficult to meet the personalized needs of specific surgeries. When the image has high contrast (such as blood vessels and normal tissue), the adjustment response may be slow.

Advantages: It solves the problem of uneven brightness in traditional automatic dimming, and can simultaneously ensure the clarity of near and far scenes, which is conducive to the discovery of tiny lesions . The intelligent algorithm can predict the changes of the lighting environment and realize proactive adjustment with fast response speed. It is compatible with ultra-high-definition imaging systems and can give full play to the performance of high-resolution sensors, which is of great significance for the early screening of tumors.

Disadvantages: The technology is complex, relying on high-performance hardware platforms and self-developed algorithms, resulting in high equipment costs . At present, it is only applied in mid-to-high-end endoscopic systems, and the popularity is low. The algorithm has high requirements for the computing power of the host, and the energy consumption is higher than that of traditional dimming modes.

Advantages: It can significantly improve the image contrast and color gamut, making the details of the lesion (such as the shape of blood vessels) more clear . The independent control of regional brightness can avoid the interference of stray light and improve the accuracy of diagnosis. It is compatible with 4K and other ultra-high-definition imaging technologies, and is the core dimming mode of high-end endoscopic systems.

Disadvantages: The system structure is complex, requiring multiple light source control units and high-precision image analysis algorithms, with high research and development and production costs. The debugging of regional brightness is difficult, and improper parameter setting may lead to obvious brightness division lines in the image. It is not suitable for low-resolution endoscopic systems, and the application scope is limited.

Different dimming modes have their own applicable scenarios. Manual dimming is suitable for primary medical institutions and simple endoscopic examinations (such as routine gastroscopy); automatic dimming is widely used in general clinical diagnosis and treatment, balancing efficiency and stability; adaptive fusion dimming and local dimming are mainly used in high-end endoscopic systems for early tumor screening and precise surgery .

With the development of artificial intelligence and ultra-high-definition imaging technology, the dimming mode of endoscopic camera modules will tend to be intelligent, precise and personalized. In the future, the dimming system may combine with technologies such as lesion recognition algorithms to realize adaptive brightness adjustment for specific lesions, further improving the level of endoscopic diagnosis and treatment.