JPEG2000 is based onwavelet transform Image ofCompression standard, created and maintained by the Joint Photographic Experts Group.JPEG 2000 is generally considered to replace JPEG in the future (based ondiscrete cosine transform ）The next generation of image compression standard.The extension of a JPEG 2000 file is usuallyjp2, MIME type is image/jp2.
Chinese name
JPEG 2000
Based on
Image compression standard of wavelet transform
Support
More sophisticated progressive display and download
JPEG2000 has a higher compression ratio, and will not produce the originaldiscrete cosine transform Blocky blur artifacts produced by JPEG standard of.JPEG2000 also supportsLossy compressionandlossless compression。In addition, JPEG2000 also supports more complex progressive display and download.
JPEG2000 isInternational Organization for Standardization(ISO), document code isISO/IEC 15444-1:2000。Although JPEG2000 has certain advantages in technology, by 2019, the network will use JPEG2000 technology to produceimage fileThe number is still small, and most browsers still do not have built-in support for JPEG2000 image file display.However, JPEG2000 still has better performance under lossless compressioncompression ratio, so JPEG2000Image qualityHighly demandingMedical imageIt has been widely used to a certain extent in analysis and processing.In addition, the images of the cinema projection system are basically stored and played in the format of jpeg 2000
Relevant standards
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Published JPEG2000 standards include ISO/IEC 15444-1:2000.In addition, some additional standards related to JPEG2000 are also being developed and discussed, such asJPEG2000 Securityimage transmission (JPSEC) andConnection based JPEG2000 image browsing(JPIP), etc.
Technical discussion
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The goal of JPEG 2000 is not only to surpass JPEG in performance, but also to add and enhance features such as scalability and editability.
Technical details
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Wavelet+EBCOT
contrast
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Comparison between JPEG2000 and JPEG
stayLossy compressionThe obvious advantage of JPEG2000 is that there is no JPEG compressionMosaicdistortioneffect.The distortion of JPEG2000 is mainlyFuzzy distortion。The main reason for fuzzy distortion is thatCoding processAttenuation of medium and high frequency to a certain extent.The traditional JPEG compression also has the problem of blurring and distortion.
As far as the overall image compression performance is concerned, there are some articles that may exaggerate the performance of JPEG2000.In fact, at lowCompression ratioIn this case (for example, the compression ratio is less than 10:1), the traditional JPEGimage qualityIt may be better than JPEG2000.JPEG2000 has obvious advantages only when the compression ratio is relatively high.On the whole, compared with traditional JPEG, JPEG2000 still has a largeTechnical advantages, usually the compression performance can be improved by more than 20%.Generally, when the compression ratio reaches 100:1, the JPEG compressed image has been seriously distorted and is difficult to recognize, but the JPEG2000 image can still be recognized.Lossy compressionGenerally used for image quality or distortionPeak signal-to-noise ratio（PSNR）Indicators.Although the peak signal to noise ratio can not fully reflect the human visual effect, it is still a relatively popularQuantitative indicators。
Copyright and patent issues
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JPEG2000 has copyright and patent risks.This may be one of the reasons why JPEG2000 technology is not widely used at present.The JPEG2000 standard itself does not have licensing fees. However, because a large number of algorithms in the core part of the coding are patented, it is generally believed that it is unlikely to avoid thesePatent feeDevelop free commercial useencoder。
