Tag: Image Sensing CMOS CCD
This article refers to the address: http://
Sensor type: We often say that the sensor of the digital camera is quite similar to the film of the traditional camera. The sensor is the core of the digital camera and the most critical technology. It is used to receive the light passing through the lens and convert these optical signals into Device for electrical signals. At present, there are two core imaging components of a digital camera: one is a CCD (charge-coupled) component; the other is a CMOS (complementary metal oxide conductor) device.
CCD Photosensitive Device: CCD is called Charge Coupled Device, and Chinese translation is charge coupled device. It is made of a high-sensitivity semiconductor material that converts light into electric charge, and then converts the electrical signal into a digital signal through an analog-to-digital converter chip. The digital signal is compressed and transmitted to the computer via the USB interface. The captured image.
CMOS Photosensitive Device: CMOS is called Complementary Metal-Oxide Semiconductor, which is translated into a complementary oxidized metal semiconductor. CMOS manufacturing technology is no different from general computer chips, mainly using semiconductors made of silicon and germanium, which coexist with N (band - electric) and P (with + electric) levels in CMOS. The semiconductor, the current generated by these two complementary effects can be recorded and interpreted by the processing chip into an image.
The difference between CMOS and CCD: The main difference between CCD and CMOS is that CCD is integrated on semiconductor single crystal material, and CMOS is integrated on semiconductor material called metal oxide. There is no essential difference in working principle. CCD Only a few manufacturers such as Sony, Panasonic, etc. master this technology. Moreover, the CCD manufacturing process is more complicated, and the price of the camera using the CCD will be relatively expensive. In fact, after the technical transformation, the gap between the actual effects of CCD and CMOS has been reduced a lot. Moreover, the manufacturing cost and power consumption of CMOS are lower than that of CCD, so many CMOS sensors used by camera manufacturers. Imaging: The imaging transparency and sharpness of the CCD are very good under the same pixel, and the color reproduction and exposure can be basically accurate. The products of CMOS are generally transparent, the color reproduction ability of the object is weak, and the exposure is not very good. Due to its physical characteristics, the imaging quality of CMOS and the CCD still have a certain distance. However, due to its low price and high integration, it has been widely used in the field of cameras.
At present, the digital cameras sold in the market are mainly CMOS photosensitive devices. In the products using CMOS as the photosensitive component, through the use of image source automatic gain enhancement technology, automatic brightness, white balance control technology, color saturation, contrast, edge enhancement and gamma correction and other advanced image control technology, you can Achieve comparable results to CCD cameras. Due to market conditions and market development, there are only a few manufacturers of CCD image sensors for cameras. The main reason is the high cost of CCD image sensors.
Reasonable use of the camera: First of all, do not use it in a backlight environment, especially not directly pointing to the sun, otherwise the tragedy of "magnifying glass ants" will happen on your camera. Secondly, the ambient light should not be too weak, otherwise it will directly affect the image quality. There are two ways to overcome this difficulty. One is to enhance the surrounding brightness, and the other is to select a product that requires a minimum illumination. Now some cameras can reach 5lux.
The last thing to notice is to use the lens zoom reasonably. Don't underestimate this. With the correct adjustment, the camera can also have the function of close-up shooting.
Sensor Pixels: There are many photoreceptors on the image sensor that convert light into electric charge to form an electronic image that corresponds to the scene. In the sensor, each photosensitive unit corresponds to one pixel (Pixels). The more pixels, the more it can sense more object details, and the clearer the image. In order to improve the sharpness of the image, in addition to improving the image processing, increasing the number of photosensitive cells of the sensor, that is, increasing the sensor pixel is also a major method. Most of the mainstream cameras on the market today use 300,000 pixels, that is, there are about 300,000 photosensitive cells in the sensor. The corresponding imaging resolution is 640 x 480 (ie equal to 307200 pixels). Maximum resolution: Resolution is a parameter used to measure the amount of data in a bitmap image, usually expressed as dpi (dot per inch). The resolution of the camera refers to the ability of the camera to analyze the image, that is, the number of pixels of the image sensor of the camera. The highest resolution is the size of the camera's ability to resolve images at the highest, the highest number of pixels in the camera. The highest resolution of the more popular 300,000-pixel CMOS on the market is generally 640×480, and the highest resolution of the 500,000-pixel CMOS is generally 800×600. The two numbers of resolution represent the units of the number of points in the length and width of the picture. The aspect ratio of a digital picture is usually 4..3. In practical applications, the higher the pixel, the better the quality of the captured image, but on the other hand, the higher the pixel, the better. For the same picture, the higher the pixel, the better the ability to parse the image. But the amount of data it records is much larger, so the requirements for storage devices are much higher. If you use the camera for web chat or video conferencing, the higher the resolution, the more network bandwidth you need. Therefore, consumers should pay attention to this aspect, should choose a pixel suitable for their own products according to their needs.
It is worth noting that some resolutions refer to the interpolation resolution that these products can achieve with software. Although the accuracy of the obtained images can be appropriately improved, there is still a certain gap compared with the hardware resolution. Maximum number of frames: The number of frames is the number of pictures transferred in 1 second. It can also be understood that the graphics processor can be refreshed several times per second, usually expressed by fps (Frames Per Second). Each frame is a still image, and the rapid and continuous display of the frame creates the illusion of motion. High frame rates for smoother, more realistic animations. The more frames per second (fps), the smoother the displayed motion will be. The minimum fps to avoid unsmooth motion is 30. In addition to 30fps, some computer video formats, such as AVI, can only provide 15 frames per second. The reason why we can use the camera to see continuous images is because the image sensor continuously captures the image and transmits it to the screen. When the transmission speed reaches a certain level, the human eye cannot distinguish the time gap between the images, so everyone You can see a continuous dynamic picture.
Color Digits: The number of color bits is also called the color depth. The color depth indicator of the camera reflects how well the camera can record the hue. The higher the value of the color bit, the more realistic it is to restore the details of the highlights and shadows. The number of color bits is expressed in units of binary bits (bits), and the number of bits is used to indicate the number of colors. At present, all the cameras have 24 bits of color (that is, 24 colors that can express 2), and can generate true color images. With a high number of color bits, you can get a larger color dynamic range. In other words, the distinction between colors can be more delicate. The most common camera is 24-bit, and a 30-bit camera is rarely seen. Specifically, each of the primary colors in the general camera is represented by 8 or 10 bits, and the total number of color bits of the three primary colors red, green, and blue is the number of primary color bits multiplied by 3, that is, 8×3=24 bits or 10×3. = 30 digits. The color number of the camera reflects the number of colors that the camera can correctly represent. Taking 24 bits as an example, the three primary colors (red, green, and blue) each occupy an 8-bit binary number, which means that the red color can be divided into 2 to 8 powers = 256. The same is true for green and blue. Then their combination is 256 × 256 × 256 = 16777216, which is about 16 million colors, and 30 can represent 1 billion. The higher the color depth value, the more realistic the color can be restored.
Imaging distance: To understand the imaging distance of the camera, you need to introduce a concept of hyperfocal distance. The hyperfocal length refers to the distance that can be clearly imaged after the focus point. The camera generally uses the principle of hyperfocal distance, that is, the short-focus lens can be more clearly imaged after a certain distance, and the focusing function is omitted. Of course, this “clearness†is not an absolute concept, and the scene in the hyperfocal range is not really clear imaging. Since the scene is not in the focus point, the blur is affirmative, but the degree of blur is generally acceptable to humans. The camera imaging distance refers to the range from the closest distance to the infinity that the camera can image relatively clearly. For example, some cameras have an imaging distance of 5cm to infinity, which means that 5cm is the closest imaging distance, and the scene after this distance will be relatively clear. For the average user, if you just install it on your computer for video chat, then the “Super Focus†mode focus from 5cm to infinity is enough.
Focus mode and range: The focus mode of the camera generally refers to manual focus and auto focus. Manual focus usually requires the user to manually select the focus distance of the camera. In autofocus, the camera detects the subject, determines the position of the object, and drives the lens of the lens to focus. The focus range is the range from the closest point to the farthest point at which the camera can focus. For example, some cameras have a focus range of 15cm to infinity, which means that the closest focusing distance is 15cm, and within 15cm, the focus cannot be completed. Even if it is focused, the resulting image is not clear.
Lens: The lens of the camera is a device that images the subject on a sensor (CCD or CMOS), which usually consists of several lenses. From the material point of view, the camera lens can be divided into plastic lens (Plastic) and glass lens (Glass). Generally, the lens structure for the camera is: 1P, 2P, 1G 1P, 1G 2P, 2G 2P, 4G, etc. (P and G here represent plastic lens and glass lens respectively, such as 1G 1P, the lens of this camera is made of a piece of plastic. The lens and a piece of glass lens). The more lenses, the higher the cost; glass lenses are more expensive than plastic. Therefore, a good quality camera should be a glass lens, the imaging effect will be better than the plastic lens, glass translucency and imaging quality have a greater advantage, more commonly used in higher-end cameras. In order to reduce the cost, most of the camera products on the market generally use plastic lenses or semi-plastic semi-glass lenses (ie: 1P, 2P, 1G 1P, 1G 2P, etc.). The lens usually has two more important parameters. One is the aperture, which is a device mounted on the lens to control the amount of light reaching the sensor through the lens. In addition to controlling the amount of light passing through, the aperture also has the function of controlling the depth of field, that is, the larger the aperture, the smaller the depth of field.
The other is the focal length, which is basically the distance from the center point of the lens to the sharp image formed on the sensor plane. The focal length of the lens determines the size of the image formed by the object captured by the lens on the sensor. Assuming that the same object is photographed at the same distance, the longer the focal length of the lens, the larger the image formed by the object.
Camera compression ratio: The compression ratio is the ratio between the original size of the image file and the compressed image. In general, the original file of the image is very large and must be image compressed for fast transfer and smooth playback. The compression ratio is the parameter that measures the size of the image compression. In general, the compression ratio of the camera is mostly 5..1. That is, if the image size of 30 seconds before uncompressing is 30 MB, then after compressing the image according to the compression ratio of 5..1, its size becomes 6 MB. The larger the compression ratio, the worse the image quality, and the larger the compression ratio, the smaller the space of the generated image is, which is beneficial for network transmission and file preparation.
Field of View: The field of view represents the maximum range that the camera can observe, usually expressed in terms of angles. The larger the field of view, the larger the range of observations. For example, some cameras have a field of view of 50 degrees and some are 58 degrees. The latter can capture a larger range of scenes at the same distance from the former. At present, the resolution of the general camera is about 52 degrees, and even more than 180 degrees, 360 degrees (the camera base is fixed, the lens can be rotated for one week).
Features: Network video: After connecting the computer and installing the corresponding driver software, the camera can be combined with the corresponding network chat tools such as Tencent QQ, MSN, etc. for network chat. Still photo shooting: After connecting the computer and installing the corresponding driver software, the camera can take digital photos. Since the camera does not have an LCD display, it is generally the case that the computer's display is used as a viewfinder. The camera also has certain limitations in taking digital photos. The low resolution is one aspect. The limitation of the shooting range is also obvious - many cameras must be connected to a computer to take still photos.
Surveillance: It is the real-time monitoring of the scene by connecting the scene to the scene in real time via a camera and then connecting it to a TV or computer via a cable (a camera that now has a wireless transmission). Components: housing shell head, housing base, main control chip, lens, image sensor, PCB motherboard and peripheral circuits, USB cable, infrared diode; outer packaging, inner card or plastic, drive plate, manual, warranty Card and certificate, etc.; Master chip (DSP): The central processor, the resolution of the camera (pixel) and the frame rate depends on its materials; pixels and frequencies are important indicators for judging the performance of the camera. The mainstream product pixel value is generally 10W~30W. The frequency is usually 15~30 frames. Commonly used are: Zhongxing Micro 301P, SOIXN (Songhan) Lingyue TP6800, Sunplus 561A. At present, Zhongxing Micro 301P chip has high recognition in this field due to its outstanding performance. Now it has accounted for more than 70% of the DSP market share of the camera; SOIXN (Songhan) chip is gradually recognized by consumers as a cost-effective, Sunplus 561A The chip is mainly used for the manufacture of 10W pixel camera heads with low cost; while the Lingyue TP6800 is in the survival period due to its own positioning and compatibility issues;
Image sensor + lens: The lens and sensor are important indicators for judging the imaging effect of the camera. The image imaging effect of the camera depends on the materials of these two important components. In terms of photographic camera, CCD design is often used because of the high requirements, and the image requirements of the camera are not so high. The CMOS applied to the lower image can meet the needs. And CMOS is a big advantage. The cost is relatively low compared to CCD, and the power consumption is much smaller. The lens is generally divided into plastic lens and glass lens. In terms of cost and performance, the glass lens has high price and high quality. Some lenses are coated with an iris on the basis of the glass to enhance the filterability. The important indicator for judging the pros and cons of the lens is the amount of light passing through. The smaller the value of the light flux f, the larger the amount of light passing through, and the higher the light transmittance. The more saturated the color, the better the imaging effect; the image sensors are commonly used: Hyundai 7131R, Micron 360, OV7630, OV7660. At present, Hyundai 7131E has been discontinued. The market is mainly divided by Hyundai 7131R and Micron 360. In terms of imaging effect, Micron 360 is superior to Hyundai 7131R, and the price is slightly higher than that of Hyundai 7131R. OV7630 is slightly worse in image performance but low in price. The OV7660's imaging effect is similar to that of Hyundai 7131R and Micron 360 (but better in the low-light situation than the former).
Totally different from other flower lighting, the flowering glow by itself. One hundred flowers just two LED light source, that will make long life span time and low maintenance cost. Natural design for outdoor landscape.
Customized service for fiber optic flower is available, such taller, shorter and different color effect.
Fibre Optic Flower Lamp,Led Fiber Optic Flower Light,Fiber Optic Light,Fiber Optic Lamp
ZHONGSHAN G-LIGHTS LIGHTING CO., LTD. , https://www.glightsled.com