Compression and decompression for certificate photo

Abstract

A method for compressing / decompressing photo of certificate holder includes analyzing data of image containing head photo to support compressing / decompressing image data of interesting region, applying conformal wavelet algorithm for enabling to store color or black / white image with high compression ratio and enabling to carry out high quality of decompression on it. In the method, it is easy to store head photo data of IC cardholder into card with form of IC card data.

Description

technical field [0001] The invention relates to a method for image data processing, in particular to a method for compressing and decompressing a certificate portrait photo. Background technique [0002] In the existing image compression technology, the following three algorithms are mainly used: JPEG, JPEG000 and fractal compression. The method of JPEG and JPEG2000 adopts transform first (JPEG adopts discrete cosine transform, JPEG2000 adopts wavelet transform), then quantizes, and finally encodes, which can be applied to various image compression. Usually when the compression factor is within 20 times, the quality of the compressed image is better, but when the compression factor exceeds 20 times, for example, JPEG compressed images will appear blurred phenomena such as mosaics; although the fractal compression method can achieve large-scale compression, but the fractal The algorithm is limited to images with self-similar characteristics, such as natural scene images such...

AI Technical Summary

Problems solved by technology

At present, the size of the original photo of the ID card collected is about 150KB. After the original photo is compressed to the specified size by using the currently known image compression method, the compressed photo cannot meet the certification requirements, that is, the existing technology cannot achieve the expected effect.

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