What Is an Imaging Agent?

An imaging process refers to a process in which an image is focused on an imaging element through an optical system such as a signal processing and imaging system, and the image is stored in a storage medium.

1.The lens focuses the scene image on the film

2.on-chip

a) Light is projected through the lens to

Digital cameras use electronic components for imaging instead of film-this is the most fundamental difference between digital cameras and traditional cameras. The imaging devices of digital cameras are mainly divided into two categories:

CCDabbreviation of English ChargeCoupleDevice, Chinese name "Charge Coupled Device".

CMOSabbreviation of English ComplementaryMetal-OxideSemiconductor, Chinese name is "Complementary Metal Oxide Semiconductor".

CCD CCD imaging process

1) CCD is currently the mainstream imaging device, mainly divided into:

(1) RGB primary color CCD: This is the most commonly used CCD in digital cameras.

(2) CYGM complementary color CCD: Some Nikon digital cameras have used this complementary color CCD earlier.

(3) RGBE four-color CCD: This is Sony's latest CCD, which has an E (Emerale, emerald) color than the RGB primary color CCD.

2) SuperCCD: It is a patented technology of Fuji Corporation in Japan. The Chinese name is Super CCD, which evolved from CCD and has now developed to the fourth generation.

3) CMOS: As a digital camera imaging device, it has not been around for a long time, but it has developed very quickly. It has a tendency to fight with the CCD chamber. The pixel arrangement in its basic structure is not essentially different from the RGB primary color CCD. Canon is a major supporter of the CMOS camp.

CCD CCD characteristics during imaging

CCD technology is mature and imaging quality is good. After all, it is the most widely used imaging element now, but it also has its disadvantages:

1) Power consumption is large. Early digital cameras had the "reputation" of "electric tiger", and one of the main reasons came from the CCD. Although the low-power polysilicon display and other low-energy components are used to reduce the power of the camera to a certain extent, the CCD is still a big power consumer of digital cameras-the CCD keeps working at any time from the moment the digital camera is turned on. Ground consumes a lot of electricity.

2) The process is complicated and the cost is high. The complex structure of a CCD determines the complexity of its manufacturing process. So far, only a few electronics giants can produce CCDs.

3) Pixel enhancement is difficult. The first two shortcomings of CCD also directly lead to this shortcoming. The improvement of CCD pixels is only through two ways:

First, keep the unit area of the photosensitive element unchanged and increase the CCD area, and integrate more photosensitive elements on the large-area CCD. However, this method will result in lower CCD yield, higher manufacturing costs, and greater power consumption, which is unrealistic in the civilian field;

Secondly, the unit area of the photosensitive element is reduced, and more photosensitive elements are integrated on the existing CCD area. However, this method will reduce the unit photosensitive area of the photosensitive element, reduce the overall sensitivity and dynamic range of the CCD, and affect the image quality.

CMOS CMOS characteristics of imaging process

The development speed of CMOS has been quite good in recent years, and there is a strong tendency to compete with the CCD chamber-even the top DSLR (single-lens reflex digital camera) Kodak DCS14n and Canon EOS1Ds are adopted CMOS imaging.

Compared with CCD, CMOS has two most prominent advantages:

1) Low price and simple manufacturing process. CMOS can be produced using ordinary semiconductor production lines, and does not require special production processes like CCD, so the manufacturing cost is much lower. In addition, CMOS size and yield are not as good as CCD.

2) Low power consumption. Although the filter layout of the CMOS is not much different from that of the CCD, the circuit structure of the photosensitive unit is very different. Each CMOS sensor has an independent charge / voltage conversion circuit, which can independently amplify and output the electrical signals after photoelectric conversion. This is much faster than collecting all the signals and then amplifying and outputting them. In addition, the CMOS sensor only works during light imaging, so it saves more power than CCD. However, CMOS also has disadvantages. If there are many imaging actions when using a digital camera, CMOS will generate heat due to changing current during frequent startup processes, resulting in clutter and affecting image quality.

Basic parameters of imaging elements during imaging

The imaging element is the core of a digital camera, so it is necessary to correctly understand some of its important parameters. This will help to understand the basic performance of a digital camera and how to choose a digital camera.

• Total pixels-Total pixels is the number of imaging units on the imaging element of the index code camera. A total pixel of 5.24 million CCDs means that there are 5.24 million imaging units integrated on it. Digital has basically used total pixels when indicating its performance.

• Effective pixels-When a digital camera is imaging, the edge of the photosensitive element will be blurred due to the diffraction of light. To ensure the quality of the imaging, the imaging of this part of the photosensitive element will be discarded, so the photosensitive unit cannot be used 100%. The pixels that are used, that is, the pixels that get the final image, become effective pixels.

• Dimensionsrefers to the length of the diagonal of the photosensitive element, and the common unit is inches. Common ones are 1 / 1.8 inch, 1 / 2.7 inch, 2/3 inch, etc. In general, the larger the size of the photosensitive element, the better the performance and imaging effect of the element. In addition, the digital camera's photosensitive element generally uses an aspect ratio of 4: 3, and the more special one has 3: 2.

• ISOrefers to the sensitivity of the light sensor to light. The larger the value, the higher the sensitivity. Common values are 50, 80, 100, 160, 200, 400, etc. At present, the highest ISO value of digital camera's photosensitive element can reach 3200. It should be noted that although a high ISO value can improve the imaging quality of a digital camera in a dark environment, the higher the ISO, the more obvious the impact on the picture quality and the more noise appears.