Camera related knowledge

Digital camera (camera)

It is a digital video input device, which uses photoelectric technology to collect images, and converts the "point current" of these representative pixels into 0 and 1 of digital signals that can be processed by the computer through internal circuits, unlike a video capture card. In that way, first use an analog acquisition tool to collect the image, and then complete the input of the image through a dedicated analog-to-digital conversion component.

sensor
It is an important part of the digital camera, which is divided into CCD and CMOS according to the different components. CCD (Charge CoupLED Device) is a high-end technology component used in photography and photography, and CMOS (Complementary Metal-Oxide Semiconductor) is used in products with lower image quality. The manufacturing cost is lower than the CCD, and the power consumption is much lower. Although there is a big difference in technology, the performance gap between CCD and CMOS is not very big, but the requirements of the CMOS camera on the light source are higher, but now the problem has been basically solved. At present, the size of the CCD element is mostly 1/3 inch or 1/4 inch. At the same resolution, it is better to choose the larger element size.

Sensor pixels

It is one of the important indicators to measure the camera. Some products will be marked with 300,000 pixels or 350,000 pixels in the box. In general, products with higher pixels have better image quality. But on the other hand, it is not that the higher the pixel, the better. For the same screen, the higher the pixel, the stronger the ability to parse the image. In order to obtain a high-resolution image or screen, the amount of data it records must be large. Much more, the requirements for network transmission bandwidth and storage equipment are much higher.

The highest resolution is the maximum resolution that can be achieved by the still images captured by the camera and the collected dynamic images, but the image files generated at the highest resolution generally have a larger amount of data.

Interface Type

The connection method of the camera is basically realized in three ways: interface card, parallel port and USB port. The interface card type is generally realized by a dedicated camera card. Most manufacturers will optimize or add video capture functions for the camera, which has a greater advantage in terms of image quality and video stream capture. However, due to the different design of the interface cards of various manufacturers, the products cannot be used universally, and the price is not cheap. Such products are worth the choice of users who need to pursue higher picture quality. The advantage of the parallel port method is that it has strong adaptability and each machine has a parallel port. However, the data transmission rate is slow and the practicality is greatly reduced. For ordinary users, it is still acceptable. The USB interface mode is currently the mainstream trend. Existing motherboards support the USB connection mode, and the power consumption of the current camera is relatively small, and the power provided by the USB can work, so that the external power supply can be omitted.

Color bits

Also known as color depth, the color depth index of a digital camera reflects how accurately the camera can record tones. The higher the number of color bits, the more likely it is to more accurately restore the details of bright and dark parts. At present, almost all digital cameras have 24 color bits, which can generate true color images.

Video capture speed

Video capture capability is one of the functions that users are most concerned about. Many manufacturers claim that the maximum video capture capability is 30 frames per second, but the actual use is not satisfactory. At present, the video capture of the camera is realized by software, so the requirements on the computer are very high, that is, the processing power of the CPU must be fast enough, and secondly, the capture requirements are different depending on the requirements of the picture. Now the maximum resolution of the camera to capture the picture is 640 × 480. Under this resolution, no digital camera can achieve the capture effect of 30 frames per second, so the picture will jump. It is more realistic to rely on the combination of hardware and software at 320 × 240 resolution to achieve the standard rate capture index, so for complete video capture speed, it is only a theoretical index. Users should choose the appropriate products according to their actual needs to achieve the desired effect.


The future of the camera

According to the "Moore's Law" of hardware development in the IT industry, digital cameras also follow its development law, and I believe that it will develop rapidly in the next few years. From the current market situation, the factors that restrict the development of the camera are mainly due to the following reasons:

1. The camera market started late, with low consumer awareness and acceptance, so the penetration rate is low, and the market capacity is not increasing fast enough, and certain guidance is needed to promote market consumption.

2. The actual application of the camera is not wide enough, and has certain limitations. It is still sold as a consumer product. Consumers just use it as a tool for video chat, making simple personal video sets, and simple monitoring systems.

3. The limitations of computer hardware, such as the resolution of computer graphics cards and monitors, and the speed of the USB 1.1 interface, affect the true popularity of high-resolution cameras.

From a personal point of view, the future development trend of digital cameras is:

1. High pixel (500,000, 800,000), high-quality image sensor (CCD), high transmission speed (USB2.0 or other interface) camera will be the future development trend;
2. Specialization (only used as a professional video input device), multi-functionalization (with other functions, such as a flash drive, and the trend toward digital cameras, and it is also conceivable that future cameras can have the function of scanners), etc. are also in the future Development trend;
3. More user-friendly, easier to use, and more practical application functions are the real needs of customers.

Note: The state requires that non-specific public places must not be installed with cameras, nor can they be installed outside of their own homes to protect the legitimate rights of the people.