Surface Centrifugal Pump,Surface Centrifugal Pumps,Homemade Centrifugal Pump,Self-Priming Surface Centrifugal Pump Zhengzhou Shenlong Pump Industry CO.,Ltd , http://www.waterpump-manufacturer.com
After a period of groping and research, the author concludes that it is necessary to grasp and solve the following problems in map detection work:
First, enhance the image processing to identify the origin of the fuzzy video image
There are many technical factors affecting the quality of surveillance images. This article mainly analyzes and studies from the perspective of map detection applications.
1. Quality standards vary: Due to the unbalanced economic development, the performance and technical standards of the video surveillance systems installed by various units and departments are not uniform, and the relevant national regulations are not very sound, resulting in the application of video surveillance by the above units and departments. There is also a large quality difference in the system.
2. The use of video is not the same: The needs of the surveillance video and the purpose of use are inconsistent between the construction unit and the competent person, resulting in a different picture quality due to the different emphasis. Therefore, a series of problems arise when using surveillance video images as evidence or clues.
3, video image compression / transmission / storage / decompression of different quality: Although the current monitoring technology and the corresponding equipment has been widely used in China, but due to the various manufacturers in order to compress storage space and reduce costs and continuously increase the compression ratio . After the analog video image signal is input to the digital signal, the image quality has been affected more or less by the compression, transmission, storage, and decompression. The image clarity, grayscale, color reproduction, Real-time performance attenuates to varying degrees.
4. Video capture is affected by the external environment and the internal noise of the device: There are many factors that affect the clarity of the image. For example, if the outdoor illumination is not uniform enough, the video image will be too grayscale; the image obtained by the CCD (camera) passes through the A/D ( Digital-to-analog conversion. This function is implemented in the image system by a digital acquisition card.) Conversion, line transmission, etc. all generate noise pollution. Therefore, the image quality is inevitably reduced. The lighter ones show that the images are not clean and it is difficult to see the details; the heavier ones show that the images are not clear, and even the outline cannot be seen.
4. Man-made secondary loss of video image quality: Many manufacturers artificially create their own video images for commercial purposes and need to use an exclusive browser to play. However, all image processing software used in image detection work is not fully compatible with the conditions. All video formats on the market cause the downloaded/extracted video to need to be formatted in the post-processing or directly use the video download mode, and the conversion format or the video download itself is a loss process.
Second, choose the correct download method and video conversion format
Image format is the root cause of image quality. Due to the influence of network bandwidth and storage costs, video surveillance equipment produced by all equipment manufacturers will adopt video compression coding technology. Although it can guarantee the application requirements of most users, the vast majority of video picture quality is for the investigators. Far from meeting the requirements. Therefore, the first step of map detection work is to minimize the secondary loss of the quality of the monitoring image resources, that is, to minimize losses in the links of copying, downloading, or extracting. In actual work, map surveyors need to master the following aspects of common sense and techniques to reduce the loss of image quality in this area:
1, familiar with the types of image resources Video image resources can be roughly divided into three categories: First, the city's technical defense network system image resources, and second, each unit based on DVR storage of video system image resources, and the third is a variety of relatively backward computer-based + The board's monitoring system stores image resources on the hard disk.
2. Grasp the most useful download method The first type belongs to the metropolitan area network type system. It is very convenient to use the method of downloading the IP address of the client in the network to obtain video data. The second type of system is tested and downloaded using IE browser. The method is faster and more reliable; the third type can only be solved by hard disk copying or recording because there is no RJ45 interface.
Several key parameters of image enhancement technology 3. Converting video image format is an important part of image enhancement Through our experience in practical work, the format of device storage in Table 1 is basically compatible with various software. If you encounter video formats that are incompatible with various software systems, you can generally use the fomatfactory, raccoon nest, or universal format converters to do the conversion. No matter what software you use for conversion, you must use H.264-based AVI format video files. As for the above-mentioned software incompatible formats, either to the device manufacturer to ask for a conversion tool, or only use the way of recording, recording as much as possible using professional acquisition equipment, even though, the quality of the recorded video is not good.
Third, understand several key parameters of image enhancement technology and its internal links
In the map detection work, the image processing after the interception of video images is a very important task, and the enhancement in image processing is the basic skill that the map detection staff must master. Image processing generally refers to digital image processing. The digital image refers to a large two-dimensional array obtained by sampling and digitizing with a digital camera. The elements of the array are called pixels. The value of the array is an integer called a gray value. The main contents of image processing include image compression, enhancement and recovery, and matching, description and identification.
1. Image-enhanced content The image-enhanced content includes the adjustment of brightness, chromaticity, saturation, and the use of histograms or curves to adjust the gradation, as well as the image sharpening, noise reduction, lossless amplification, and other processing.
2. Parameters to be used for image enhancement Although the human eye is highly discriminating and can recognize thousands of colors, in many cases, the image is blurred or even invisible to the human eye through image enhancement techniques. , can make blurry or even invisible images become clear and bright. Improvements in image quality also result in image enhancement. Image enhancement does not consider the cause of image quality degradation. It only selectively enhances the features of interest in the image and weakens the unwanted features. The purpose of this work is to improve the intelligibility of the image and improve the useful information of the viewer. the amount. In practical applications, we mainly use various image processing software to adjust the image parameters and maximize his useful information. The parameters to be processed by the image enhancement mainly include: color scale, curve, color, brightness, contrast, saturation, and the like. These parameters can be easily dealt with using software such as light and shadow magic hands, photoshop and more.
3, flexible use of software to process image color scale parameters, to avoid pixel loss Although there are many software on the market can adjust the image parameters, but the result after processing varies from person to person. The reason for this is that the reason for the lack of image parameters has not been identified. Once you find the right cause, you can easily use the software tools to enhance it and restore the image. After a period of groping, using the color scale to adjust the brightness, the loss of image contrast and saturation is small, and it is very intuitive to reduce the loss of pixels and preserve the original color details as much as possible. The direct adjustment of brightness and contrast is more serious for the image quality. Lost serious. The method of adjusting the color gradation is summarized as "image enhancement gradation adjustment work method".
In the actual work of image reconnaissance, the image quality of the video images we downloaded/extracted was not high, and there often occurred incidents in which people, license plates, or video recordings could not be clearly identified. In fact, there are many reasons for poor picture quality. As a picture detection worker, regardless of the quality of the video system's engineering and equipment, he cannot artificially create video image quality in image enhancement, image conversion, and processing. Decline and loss of quality.