Hi, Community!
This topic describes the picture format--JPEG.
What is JPEG
The JPEG, full name Joint Photographic Expert Group, is also one of the most common image formats. It is the most commonly used image file format by the Joint Photographic expert Group (full foreign language: Joint Photographic Experts Group), file dropped out under the name ". Jpg" or ". Jpeg").
Developed by a software development federation, it is a lossy compression format, which can compress the image in very small storage space, and the duplicate or unimportant data in the image will be lost, so it is easy to damage the image data. Especially if the compression ratio is too high the quality of the image recovered after decompression will be reduced obviously. If the high-quality image is pursued it is not suitable to use too high compression ratio. But JPEG compression technology is very advanced, it uses lossy compression method to remove redundant image data, it can produce very rich and vivid images while obtaining extremely high compression ratio, in other words, Is can use the least disk space to get better image quality.
JPEG format is widely used, especially on the Internet and CD-ROMs. All kinds of browsers support JPEG image format because JPEG format file size is smaller, download speed. As an upgraded version of JPEG, the compression ratio of JPEG2000 is about 30% higher than that of JPEG. At the same time, it supports lossless and lossless compression.
A very important feature of the JPEG2000 format is that it can realize progressive transmission, that is, the contour of the image is transmitted first, and then the data is transmitted step by step. Constantly improve the image quality, so that the image from obscurity to clear display. In addition, JPEG2000 also supports the so-called "region of interest" feature. It can specify the compression quality of the region of interest on the image at any time. JPEG2000 can be used in traditional JPEG markets, such as scanners, digital cameras,s and so on. JPEG2000 can be used in emerging fields such as network transmission, wireless communication, and so on.
Advantages
Photographic works or realistic works support advanced compression. File size can be controlled using variable compression ratios. Support interleaving (for asymptotic JPEG files). JPEG widely supports the Internet standard.
Disadvantages
Lossy compression can reduce the quality of the original image data. When you edit and re-save the JPEG file, the JPEG mixes the original picture data with poor quality. This decline is cumulative. JPEG is not suitable for simple images with small colors, large reas with similar colors or obvious brightness differences.
