Charge coupled device image sensor CCD (Charge Coupled Device), which is made of a high-sensitivity semiconductor material, can convert light into electric charge, and is converted into a digital signal by an analog-to-digital converter chip. After the digital signal is compressed, The camera's internal flash memory or built-in hard disk card saves the data so that it can be easily transferred to the computer, and with the help of computer processing, according to the needs and imagination to modify the image. CCDs consist of many photosensitive units, usually in megapixel units. When the CCD surface is exposed to light, each photosensitive unit will reflect the charge on the component, and the signals generated by all the photosensitive units are added together to form a complete picture.
Compared with conventional negatives, CCDs are closer to the way the human eye works on vision. However, the retina of the human eye is composed of rod cells responsible for light intensity sensing and color-inducing cone cells, which cooperate to form visual induction. After 35 years of development, the CCD has been shaped and its general shape and mode of operation have been finalized. The composition of the CCD is mainly composed of a mosaic-like grid, condenser lenses, and a matrix of electronic circuits padding at the bottom. The companies that currently have the ability to produce CCDs are: Sony, Philips, Kodak, Matsushita, FUJI, and Sharp. Most of them are Japanese manufacturers.
At present, there are mainly two types of CCD photosensors, linear CCDs and matrix CCDs. Linear CCDs are used for high-resolution still cameras. They capture only one line of an image at a time, which scans the photo with a flatbed scanner. The same method. This CCD has high accuracy and slow speed and cannot be used for shooting moving objects or flash.
A matrix CCD, where each photosensitive element represents a pixel in the image, is exposed at the same time as the shutter is opened. There are two ways in which a matrix CCD can process color. One is to embed a color filter in a CCD matrix, and similar pixels use different color filters. There are two typical arrangements of GRGB and CYGM. The principle of these two imaging methods is the same. In the process of recording photos, the camera's internal microprocessor obtains a signal from each pixel and synthesizes the adjacent four points into one pixel. This method allows instant exposure, and the microprocessor can operate very quickly. This is the imaging principle of most digital camera CCDs. Because it is not the same point synthesis, which contains mathematical calculations, the biggest drawback of this kind of CCD is that the resulting image is always unable to achieve a knife-like sharpness.
Complementary metal-oxide-semiconductor (CMOS) complementary semiconductors (CMOS), like CCDs, are semiconductors that record light changes in digital cameras. The manufacturing technology of CMOS is no different from general computer chips. It is mainly made of semiconductors made of silicon and germanium, which make it possible to coexist on the CMOS with N (band-electricity) and P (band + electricity) grades. In semiconductors, the current generated by these two complementary effects can be recorded and interpreted by the processing chip as an image. However, the disadvantage of CMOS is that it is prone to noise. This is mainly due to the fact that early designs made CMOS overheated due to current changes when dealing with rapidly changing images.
In addition to the CCD and the CMOS, there is a SUPER CCD that is exclusive to Fujifilm. The SUPER CCD does not use a conventional square diode. Instead, it uses an octagonal diode in which the pixels are arranged in a honeycomb pattern and are each pixel-sized. The area is larger than the traditional CCD. As a result of the arrangement of the pixels rotated by 45 degrees, it is possible to reduce the extra space that is useless for image capturing, and the efficiency of light concentration is relatively high, and the efficiency, signal-to-noise ratio, and dynamic range are increased after the efficiency is increased.
Each pixel in a conventional CCD consists of a diode, a control signal path, and a power transmission path. The SUPER CCD uses a honeycomb-shaped eight-sided diode. The original control signal path is eliminated. Only one direction of power transmission path is required, and the photodiode has more space. SUPER CCD is more compact than the ordinary CCD in arrangement structure, in addition, the utilization rate of pixels is high, that is to say, in the same size, SUPER CCD photodiodes absorb light to a relatively high level, so that the sensitivity, signal to noise ratio and The dynamic range has been improved.
Why is the output pixel of SUPER CCD higher than the effective pixel? We know that the CCD is not very sensitive to green and is therefore synthesized with G−B−R−G. Each synthetic pixel actually has a part of the real pixels that are shared, so there is a certain gap between the image quality and the ideal state. This is why some high-end professional-grade digital cameras use 3CCD to experience the RGB trichromatic light. The SUPER CCD achieves R, G, and B pixel equivalent by changing the arrangement relationship between pixels, and it also uses three as a group when synthesizing pixels. Therefore, the traditional CCD is a combination of four pixels, in fact, as long as three on the line, wasted a, and SUPER CCD found this point, only three can be used to synthesize a pixel. That is to say, CCD synthesizes a pixel every 4 points, and each point counts 4 times; SUPER CCD synthesizes a pixel every 3 points, each point is also calculated 4 times, so the utilization rate of SUPER CCD pixels is higher than that of the traditional CCD. More pixels are generated.