Main Application of Fiber Imaging Components
At present, the main methods of image transmission are: focal plane imaging system (traditional transmission and catadioptric imaging system), CCD/CMOS image sensor imaging system and optical fiber relay imaging system. The traditional focal plane imaging system has important applications in the high-resolution and high-quality imaging of some precise optical instruments, but in order to achieve high-precision imaging, the system structure is generally complex, the volume, weight and rigidity are large. The imaging process of the CCD/CMOS image sensor is a photoelectric conversion process. The optical signal is captured by the image sensor and converted into an electrical signal for transmission. Image sensors have the advantages of high sensitivity, low noise, small structure, and high image resolution, but because they belong to electronic products, they cannot work under electromagnetic radiation, high temperature, and easy corrosion.
Compared with the previous two image transmission methods, the optical fiber relay image transmission technology has the advantages of small size, light weight, high image resolution, large spatial freedom, flexible image transmission (optical fiber image transmission beam), and easy realization of complex spatial structures. Image transmission, and at the same time, multiple optical fiber imaging devices can be spliced together through a specific spatial layout to achieve ultra-large field of view imaging. After more than half a century of development, optical fiber imaging technology has been applied to all walks of life and played a key and irreplaceable role. In the medical field, the use of flexible optical fiber imaging bundles as the main device can be used to prepare various medical imaging diagnostic equipment such as gastroscopes, colonoscopes and other medical fiber optic endoscopes.
The endoscope is mainly composed of two parts, a light guide beam and an image guide beam. First, the imaging end face of the endoscope is transported to the part of the human body to be detected, and the light guide is guided into the light source for illumination. Then, the situation of the part to be measured is imaged into the image guide beam through the objective lens, and the image is transmitted into the eyepiece through the image guide beam, which can be used for medical Personnel observe high-resolution clear images in real time. Therefore, the medical fiber optic endoscope can be used not only for the inspection of human organs, but also for endoscopic surgery.
In the industrial field, the detection and monitoring instrument prepared with the optical fiber image beam as the core device is mainly used to detect the wear degree of the internal structure of automobiles, aircraft engines and various industrial equipment without disassembly to judge whether it needs to be disassembled. repair. In addition, the optical fiber imaging bundle can also be used to prepare high-resolution flexible industrial endoscopes or probes, coupled with image sensors such as CCDs, to observe the flame conditions in boilers, or to monitor hazardous locations in various harsh environments.
In the field of large field of view and high resolution imaging, multiple fiber optic panels are used as relay imaging devices to couple the concentric objective hemispherical focal plane and the flat image sensor to form an ultra-wide-angle camera with a lateral field of view exceeding 100°, which can image pixels Wide panorama images of 100 million or more. The Lawrence Livermore National Laboratory in the United States used this structure to develop a large field of view space optical imaging payload that meets the project requirements. The team of Igor Stamenov of the Department of Electrical and Computer Engineering at the University of California, San Diego has also developed a panoramic concentric ultra-wide-angle camera with an imaging field of view of 126°×16°. Optical fiber imaging technology is gradually being realized by people because of its excellent stability and superior imaging characteristics. Therefore, the processing technology of optical fiber imaging devices is becoming more and more mature, and high-standard optical fiber imaging devices are also emerging one after another. In the future, the development trend of optical fiber imaging devices must be towards the direction of thin single filament diameter, high light area ratio, high transmittance, high resolution, high image quality, large cross-section and low dark wire breakage rate.
Because the pace of human space exploration has never stopped. In the 1990s, the United States launched the Space-Based Visible Project. The “Middle Section Space Experiment Satellite (MSX)” launched by this plan was equipped with a Space-Based Visible (SBV) detector with a field of view of 1.6°×6.4 °, designed to provide the U.S. military with orbital data related to space targets. In 2002, the United States launched a space-based infrared early warning satellite, which greatly improved the detection and cataloguing capabilities of space targets. In 2010, the United States fully launched the Space-Based Space Surveillance (SBSS) program. In 2013, Canada launched the Near Earth Object Surveillance Satellite (NEOSS) and its first military satellite, the “Sapphire” satellite, with a field of view of 1.4°. Germany also developed and prepared a microsatellite named Asteriod Finder in 2013, with a system field of view of 2°×2°. In order to achieve high-resolution imaging, various optical payloads used for space-based space target monitoring can only achieve imaging with a small field of view.
The concentric optical camera using the fiber optic panel as the relay imaging device can not only achieve high-resolution imaging, but also realize the monitoring of dynamic space targets within a large field of view. It is expected to become one of the hot development trends of space target monitoring payloads in the future. .