Video analysis technology will make the security camera in the world within the scope of the application of transformed. For example, is in the stage of development of intelligent video solution can identify specific people from millions of candidates face, in a packed stadium hall locking suspicious characters, tracked a group of terrorists, or airport monitoring suspicious behavior in the streets of downtown.
Also encouraging is that video analysis technology can also be applied in the field of security, provide people with high gold content of business intelligence. Used for inventory management, for example, or in marketing analysis traffic patterns and demographic information. However, no matter how good a video analysis software, the effect depends on the quality of the video image. Is needed to get enough analysis data, the quality of the image sensor transmit images have wide dynamic range (WDR), high signal-to-noise ratio (SNR), low image artifacts and the characteristics of accurate color reproduction. People expect of video analysis is beyond the reach of CCD camera. Whatever lighting conditions, temperature and other environmental factors change, must be able to continue to generate high quality images, while avoiding false alarms - this for traditional security based on analog CCD camera is rather difficult. Therefore, a new generation of system are analyzed with the new digital image sensor.
The limitations of the CCD camera in the field of video analysis
Due to the limited dynamic range, analogue charge coupled device (CCD) camera performance demanding in the intelligent video applications, such as excessive saturated bright area and dark area underexposure, such problems as poor color reproduction and crossover artifacts, triggering a misstatement or omission. To overcome the defects of the CCD need to evaluate and filtering effect the precision of data, to reduce the useless data resolution and waste precious bandwidth.
The dynamic range of CCD sensor co., LTD will cause excessive saturated, saturation, highlights the overflow and image artifacts such as vertical tail. Saturation phenomenon occurs, overexposed pixels in the area of a bright, all become white. Highlights overflow refers to the camera image sensor in the capture lighting intensity is very high (e.g., the sun or a bright object) limited area, color distortion. Similarly, the CCD read channel receives the excess light energy, to capture images of large areas will lose information, shown as white vertical stripes. However, many of the technologies used to repair the CCD image defects and causes the loss of luminance, color saturation and detail, make intelligent solution for video transmission of data accuracy is reduced.
CCD technology is another problem of sensor chip electronic leakage caused by the scheduling of video noise, the crosstalk performance for video streaming. This random video noise can reduce image quality, causing false positives and increase the time delay of intelligent video algorithms, which affect the real-time image processing. Algorithm will often random motion sensor noise for scene.
Frequently, cross artifacts based on the CCD camera, its performance is a serrated edge around the moving object. The cause of this phenomenon is a traditional NTSC and PAL TV standard limit, and they are useless for video analysis application.
CCD, in short, there are many limitations, such as image supersaturated, video distortion caused by random noise and various kinds of clear image artifacts, leading to low content of video data, forcing algorithm to assess or speculation, resulting in misstatement or omission of accident. In addition, to overcome the limitation of the CCD and other filtering technique is the precious bandwidth, data storage and processing time, lowering the resolution.
WDR contribution to the analysis of the video
A wide dynamic range (WDR) characteristics of the new security camera can improve the accuracy of video image, make the transfer to the analysis of the video data is more stable, higher quality.
WDR refers to the camera to the highest light and shade than to capture images. In other words, even in high contrast lighting, backlighting, glare, reflective and other unable to control or varying lighting conditions, WDR camera can capture a scene at the same time the most bright and dark areas of detail and accurate color.
WDR the unit of measurement is decibels (dB). In general, the effective analysis of the video camera is required to provide the dynamic range of 100 decibels or more, so that the same scenario can generate different lighting area with very low noise (SNR), color accurate, excellent image quality, details of outstanding high quality data.
Video analysis algorithm must constantly evaluate according to the camera to "see" things or make a best guess, to distinguish the foreground and background, stationary and moving objects, and video artifacts or other sensor is sensitive to errors and target.
WDR cameras can stable transmission of high quality data, optimization algorithm of video applications, so as to realize accurate assessment and recognition. The generated by the high quality image in the whole scene (light and shadow) correct exposure, high color fidelity, sharp characteristics, the detail is outstanding, less image artifact exists or does not exist, the video noise is low.
In addition to the image quality and color reduction, all-digital WDR camera for on-site real-time network video analysis (that is, the built-in analysis function in the camera) to provide the best data. A full digital WDR camera, having to convert data from analog to digital; And because the video analysis is done on the spot, only important events through the network transmission, thereby reducing the flow rate and time, and reduce the rate of false positives, and data storage space. Even if the data is transmitted to a central server first, then make an analysis, WDR camera could also provide analysis to digital data of the highest quality, and reduce the storage space requirements.
The DPS for video analysis technology brings new application space
New digital sensor improved security camera video image quality, in order to meet the requirements of security and analysis. Especially Pixim Digital Pixel System (r) (Digital Pixel System, DPS) super wide dynamic range technology provides the most suitable for the analysis of the video image quality.
High even in strong contrast, lighting, backlighting, glare, reflective and other unable to control or varying lighting conditions, equipped with professional image processing chip Pixim cameras can also be in a scene at the same time to capture the most bright and dark areas of detail and accurate color. Using Pixim camera was also able to vertical tail, pixel highlights overflow, shadows underexposure, bright area supersaturated, moving object cross around artifact in the common image artifacts on the CCD camera was reduced to a minimum.
By providing the best WDR (maximum 120 decibels), Pixim can in any lighting or other environmental conditions to achieve high quality video images. This technique for the analysis of video application research and development, brought infinite possibility camera manufacturers and end users.
For many important applications, such as financial services, retail shops, casinos, border, the school and place, and many related to transportation environment, including airports, seaports, train, light rail, bus and so on, the DPS technology of super wide dynamic range, high resolution, accurate color, and the lowest level of image pseudo cinema can significantly improve the effect of security.
Besides the above security purposes, the high quality images can also realize the video analysis and improve the quality of business intelligence. For example, a clear, sharp, outstanding image detail helps companies track transport carrying the goods and container, in order to improve inventory management. Retail stores can compute the number of people to enter a specific time of the day, find out the customer flow of the largest shopping corridor. Train companies can use intelligent video analysis program to track the number of each station on, hop on and off at the end of the passengers safely shut automatic doors, or according to a certain number of passengers on the train and sell votes calculated monthly ticket or other packages.
After optimization of the advantages of high quality images to video analysis. Pixim will continuously improve the level of image quality, provide excellent business information and better data, to help prevent accidents, arrest criminals.
