Camera module (CCM) introduction
Camera module, full name CameraCompact Module, hereinafter abbreviated as CCM, is an important electronic device for image capture. For the camera module, we will disassemble it to see how it works. Look at what parts it is composed of.
Principles and Components of Camera Modules
(1) Working principle: The light gathered by the object through the lens (lens) converts the light signal into an electrical signal through the CMOS or CCD integrated circuit and then is converted into a digital image signal by the internal image processor (ISP) and output to the digital signal The processor (DSP) is processed and converted into standard GRB, YUV and other format image signals.
(2) CCM includes four major parts: lens, sensor, soft board (FPC), image processing chip (DSP). The important components that determine the quality of a camera are lens (lens), image processing chip (DSP), and sensor (sensor). The key technologies of CCM are optical design technology, aspheric mirror manufacturing technology, and optical coating technology.
The lens is the soul of the camera. The lens has a very important effect on the imaging effect. It uses the principle of refraction of the lens. The light from the scene passes through the lens to form a clear image on the focal plane. It is passed through the photosensitive material CMOS or CCD The photoreceptor records the image of the scene. Lens manufacturers are mainly concentrated in Taiwan, Japan and South Korea. Lens, an industry with high optical technology content, has a relatively high threshold. Well-known companies in the industry such as Fuji Seiki, Konica Minolta, Largan, Enplas, etc.
The sensor is the core module of CCM. There are currently two widely used: one is the widely used CCD (charge-coupled) component; the other is the CMOS (complementary metal-oxide conductor) device.
The charge-coupled device image sensor CCD (Charge Coupled Device), which is made of high-sensitivity semiconductor material, can convert light into electric charges, which are converted into digital signals through an analog-to-digital converter chip. CCD is composed of many photosensitive units, usually in millions of pixels. When the CCD surface is illuminated by 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. CCD sensor modules are dominated by Japanese manufacturers, and over 90% of the global market is monopolized by Japanese manufacturers, led by Sony, Panasonic, and Sharp.
Complementary Metal-Oxide Semiconductor CMOS (Complementary Metal-Oxide Semiconductor) is mainly a semiconductor made of the two elements of silicon and germanium, making it coexist with N (charged-charged) and P (charged + charged) on the CMOS For advanced semiconductors, the current generated by these two complementary effects can be recorded and interpreted into images by the processing chip. CMOS sensors are dominated by the United States, Taiwan and South Korea. The main manufacturers include OmniVision, Agilent, Micron from the United States, Sharp Image, Original Phase, and Taishi from Taiwan, and Samsung and Hyundai from South Korea.
The image processing chip (DSP) is an important part of CCM. Its function is to transfer the data obtained by the photosensitive chip to the central processing unit and refresh the photosensitive chip in a timely and fast manner. Therefore, the quality of the DSP chip directly affects the picture quality (such as colour saturation). Degree, clarity, etc.).
FPC flexible circuit board (flexible PCB): abbreviated as "soft board", also known as "flexible circuit board", which connects chips and mobile phones. Play the role of electrical signal transmission.
The Assembly Method of the Camera Module
(1) Assembly drawing of fixed focus module
CCM is divided into the fixed-focus module and automatic zoom module. The fixed-focus module is mainly assembled by a lens, lens holder, photosensitive integrated circuit, flexible circuit board, reinforcement and steel sheet.
(2) Assembly drawing of automatic zoom module
The automatic zoom module consists of a lens, a voice coil motor, a base bracket, a photosensitive integrated circuit, a driving integrated circuit and a connector.
(3) 3D module
What happened in the legendary 3D, a few more cameras to shoot. There is also on the phone.
We understand that this is enough
Some Technical Indicators of the Camera
Next, briefly talk about some common technical indicators of the camera.
(1) Image resolution/resolution (Resolution)
QSIF/QQVGA
160 x 120
19200
QCIF
176 x 144
25344
SIF/QVGA
320 x 240
76800
CIF
352 x 288
101376
100,000 pixels
VGA
640 x 480
307200
300,000 pixels (350,000 refers to 648X488)
SVGA
800 x 600
480000
500,000 pixels
XGA
1024 x 768
786438
800,000 pixels
SXGA
1280 x 1024
1310720
1.3 million pixels
UXGA
1600 x 1200
1920000
2 million pixels
QXGA
2048 x 1536
3145728
3 million pixels (320W)
QSXGA
2592 x 1944
5038848
500 million pixels
2816 x 2112
2947392
6 million pixels
3072 x 2304
7077888
7 million pixels
3200 x 2400
7680000
7.7 million pixels
3264 x 2448
7990272
8,000,000 pixels
3876 x 2584
10015584
10 million pixels
(2), image format (image Format/Colorspace)
RGB24, 420 are currently the two most commonly used image formats.
RGB24: It means that the three colours of R, G, B are 8bit each, and can express up to 256 shades, which can reproduce 256*256*256 colours.
I420: One of the YUV formats. Other formats are: RGB565, RGB444, YUV4:2:2, etc.
(3) Automatic white balance adjustment (AWB)
Definition: It is required that the image on the screen should also be white when the object is illuminated in a different colour temperature environment. The color temperature represents the spectral components, the color of light. Low color temperature means more long-wave light components. When the color temperature changes, the ratio of the three primary colors (red, green, and blue) in the light source will change. You need to adjust the ratio of the three primary colours to achieve the color balance. This is the actual white balance adjustment
(4) Image compression method
JPEG: (joint photographic expert group) static image compression method. A compression method for lossy images. The larger the compression ratio, the worse the image quality. This format can be selected when the image accuracy is not high and the storage space is limited. Most digital cameras currently use the JPEG format.
(5) Colour depth (colour digits)
Reflecting the ability to recognize colours and the colour performance of imaging, it is actually the quantization accuracy of the A/D converter, which refers to how many levels the signal is divided into. Commonly used colour bit (bit) representation. The higher the colour depth, the brighter and more attractive the colour of the image obtained. Now the cameras on the market have reached 24-bit, some even 32-bit
(6) Image noise
Refers to the noise and interference in the image. It appears as a fixed colour noise in the image.
(7) Perspective
Imaging with the human eye is based on the principle of mutuality, which is simply the imaging range.
(8) Output/input interface
Serial interface (RS232/422): The transmission rate is slow, 115kbit/s
Parallel interface (PP): The rate can reach 1Mbit/s
Infrared interface (IrDA): The rate is also 115kbit/s, and general laptops have this interface
Universal Serial Bus USB: A plug-and-play interface standard that supports hot plugging. USB1.1 rate can reach 12Mbit/s, USB2.0 can reach 480Mbit/s
IEEE1394 (FireWire) interface (also known as link): its transmission rate can reach 100M~400Mbit/s
Conclusion
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