Digital video camera, working principle and classification of digital video camera

Digital video camera is DV, which is the abbreviation of Digital Video, which means "digital video" in Chinese. It is a digital video format jointly developed by many well-known home appliance giants such as Sony, Panasonic, JVC, Sharp, Toshiba and Canon. However, in most cases, DV stands for digital video camera.

Digital Video Camera Digital
Video Camera is DV, which is the abbreviation of Digital Video, which means "digital video" in Chinese. It is a digital video format jointly developed by many famous home appliance giants such as Sony, Panasonic, JVC, Sharp, Toshiba and Canon. However, in most cases, DV stands for digital video camera.
Features
High definition As we know, analog cameras record analog signals, so the image clarity (also called resolution, resolution or resolution) is not high. For example, the horizontal clarity of VHS cameras is mainly 240 lines, and the best Hi8 model has only 400 lines. DV records digital signals, and its horizontal clarity has reached 500~540 lines, which can be comparable to professional cameras.
Purer colors The chroma and brightness signal bandwidth of DV is about 6 times that of analog cameras, and the chroma and brightness bandwidth is one of the most important factors in determining image quality. Therefore, the colors of images shot by DV are purer and more gorgeous, reaching the level of professional cameras.
Lossless copying The signals recorded on DV tapes can be transcribed countless times without any decrease in image quality, which is also unmatched by analog cameras.
Advantages
Small size and light weight Compared with analog cameras, the size of DV machines is greatly reduced, generally only about 123mm×87mm×66mm, and the weight is greatly reduced, generally only about 500 grams.
Notes
1. Image quality is a very important technical indicator when purchasing. It refers to the resolution of the image captured by the camera, with horizontal resolution as the measurement standard. The more lines, the clearer the image. 2. Zoom performance represents the flexibility of the camera and is another important indicator. Optical zoom relies on changing the focal length of the lens to zoom, which is better. When purchasing, of course, the larger the magnification, the better. Usually, the optical zoom ratio ranges from several times to more than 20 times. Some models of cameras can also increase the optical zoom ratio through a multiplier. 3. The number of functions is also an important indicator for purchasing cameras. In addition to the necessary functions such as clock setting and various operation settings, there are also picture effects, digital editing, faders, etc., which are almost necessary for various models of cameras. Digital camera - working principle HV30 appearance The basic principle of digital camera operation is simply the conversion and transmission of light-electricity-digital signals. That is, the light signal is converted into current through the photosensitive element, and then the analog electrical signal is converted into a digital signal. The information obtained after processing and filtering by a special chip is restored to the dynamic picture we see. The photosensitive element of a digital camera can convert light into electric charge, and convert it into a digital signal through an analog-to-digital converter chip. There are two main types: one is the widely used CCD (charge coupled device) element; the other is a CMOS (complementary metal oxide conductor) device. Classification 1. Classification by use 1. Broad-level models: This type of model is mainly used in the field of radio and television. It has high image quality and comprehensive performance, but the price is high and the size is relatively large. They have the highest clarity, the largest signal-to-noise ratio, and the best image quality. Of course, the price of hundreds of thousands of yuan is not acceptable to ordinary people. For example, Panasonic's DVCPRO 50M and above models. 2. Professional-level models: This type of model is generally used in professional television fields other than radio and television, such as audio-visual education, etc. The image quality is lower than that of broadcast cameras. However, in recent years, some high-end professional cameras have surpassed the old models of broadcast-level cameras in many aspects such as performance indicators. The price is generally between tens of thousands and hundreds of thousands of yuan. Compared with consumer-level models, professional DVs are not only cooler and more eye-catching, but also have much higher configurations, such as the use of lenses with better quality performance, larger CCD sizes, etc., and are more prominent in image quality and adaptability to the environment. For friends who pursue image quality, the surprise brought by the improvement of image quality is not something that can be measured by money at all. Representative models include Sony's DVCAM series models. 3. Consumer-grade models: This type of model is mainly suitable for home use. It is used in non-business occasions where the image quality is not high, such as home entertainment. This type of camera is small in size and light in weight, easy to carry, simple to operate and cheap. In occasions where the requirements are not high, it can be used to make personal family VCDs and DVDs. The price is generally in the thousands to tens of thousands of yuan. If the home digital camera is further classified, it can be roughly divided into the following types: entry-level DV, mid-range consumer-grade DV and high-end semi-professional DV products. 2. Classification by storage medium 1. Tape type: refers to a digital camera with Mini DV as the recording medium. It was first developed by more than 10 manufacturers in 1994. It records high-quality digital video signals through 1/4-inch metal evaporation. 2. Disc type: refers to DVD digital camcorders. The storage medium is DVD-R, DVR+R, or DVD-RW, DVD+RW to store dynamic video images. It is simple to operate and easy to carry. There is no need to worry about overlapping shooting during shooting, and there is no need to waste time to rewind or play back. In particular, it can be played directly through a DVD player, saving the trouble of post-editing. DVD media is the safest and most stable of all digital camcorders. It is not as easy to wear out as tape DV, nor does it have very strict requirements for shockproof like hard disk DV. The disadvantage is that the price of DVD discs is slightly higher than that of tape DV, and the recording time is relatively shorter. 3. Hard disk type: refers to digital camcorders that use hard disks as storage media. It was first launched by JVC in 2005 and uses micro hard disks as storage media. Hard disk camcorders have many advantages. Large-capacity hard disk camcorders can ensure long-term shooting, so you don’t have any worries when traveling and shooting. When you return home and transfer the filmed material to the computer, you no longer need the cumbersome and professional video acquisition equipment like in the era of MiniDV tape cameras. You only need to use a USB cable to connect to the computer to easily export the material, allowing ordinary home users to easily experience the fun of shooting and editing video films. The size of a micro hard drive is the same as that of a CF card, and smaller than a DVD disc. It also has the longest usage time among many storage media. However, since the hard drive DV has not been around for a long time, there are still many shortcomings: such as poor shockproof performance, etc. As the price continues to drop, the number of people in demand will inevitably increase in the future. 4. Memory card type: refers to a digital camera that uses a memory card as the storage medium, such as the popular "X Easy Shoot" product, which is a transitional and simple product and is now rare on the market. 3. Classification by sensor type and number 1. Sensor type: CMOS and CCD






























CCD: Charge Coupled Device image sensor, made of a highly sensitive semiconductor material, can convert light into electric charge, and then convert it into digital signals through an analog-to-digital converter chip.
CMOS: Complementary Metal-Oxide Semiconductor, like CCD, is a semiconductor that can record light changes in digital cameras.
At the same resolution, CMOS is cheaper than CCD, but the image quality produced by CMOS devices is lower than that of CCD. So far, most consumer-level and high-end digital cameras on the market use CCD as a sensor; CMOS sensors are used as low-end products in some cameras, but some high-end products also use special CMOS as a photosensitive device, such as several high-end CMOS models of Sony.
2. Number of sensors: Single CCD and 3CCD
image sensor number refers to the number of CCD or CMOS photosensitive devices in digital cameras. Most digital cameras use a single CCD as their photosensitive device, while some mid-to-high-end digital cameras use 3CCD as their photosensitive device.
Single CCD means that there is only one CCD in the camera and it is used for photoelectric conversion of brightness signal and color signal. Since one CCD completes the conversion of brightness signal and chrominance signal at the same time, the image taken cannot meet the high requirements in color restoration.
3CCD, as the name implies, is a camera using 3 CCDs. We know that if light passes through a special prism, it will be divided into three colors: red, green and blue. These three colors are the three primary colors used in our TV. Through these three primary colors, all TV signals including brightness signal can be generated. If a CCD is used to receive each color and convert it into an electrical signal, and then an image signal is generated after circuit processing, a 3CCD system is formed, which can display the original color of the image almost intact, and there will be no color error due to the interpretation of the camera.
The development prospects of China's digital camera market
In 2008, under the environment of global economic downturn, the market demand for many digital products has been greatly challenged. However, from the perspective of the development of China's digital camera market, the overall growth momentum is relatively strong, and manufacturers are paying more and more attention to the development of the digital camera market. The frequent emergence of highlights such as changes in product structure, price bottoming, and innovation in promotion forms have made the digital camera market in 2008 very lively and thought-provoking.
While China's digital cameras are developing, some problems are also increasingly exposed. However, due to the huge potential consumer group, it is still most likely to become the largest consumer market for digital cameras.