Research On Compression Of Hologram Based On Frequency Domain Processing

Three-dimensional(3D)display and imaging technology has a wide market application space.In recent years,with the continuous deepening of research,it has been widely used in military,communications,entertainment and medical fields.However,the three-dimensional display that has been put into practical application is mostly based on the binocular parallax of human eyes,and the visual effect presented by limited depth cues is not ideal.The application of holographic technology makes true three-dimensional imaging and display a reality.It can provide continuous parallax based on head motion parallax,natural visual divergence adjustment,and all depth-cues,which has great application potential.The hologram records all the information of the object light field.It contains a large amount of data,which is extremely disadvantageous for the transmission,storage and data processing.Therefore,holographic data needs to be compressed.Hologram is composed of a large number of interference fringes containing different bright points.There is no correlation between pixels,so it is difficult to compress using existing image and video encoding methods.The research on compression coding methods of holographic data has attracted widespread attention in recent years.Based on this problem,the main research content of this paper is how to improve or integrate the existing compression algorithms to improve the compression efficiency of holograms and minimize the quality loss of reproduced images.The remaining of this paper is structured as follows:First,the research progress of holographic compression technology is briefly summarized.This paper introduces the research significance of holographic data compression,international mainstream technology and methods,and potential research solutions in the future.Among the international mainstream views,the existing holographic compression coding methods are divided into three types: quantization-based,transform-based and standard-based methods.The advantages and disadvantages of these three methods are introduced and analyzed respectively.This provides theoretical basis and research ideas for the methods proposed in this paper.Secondly,based on the existing image and video compression coding methods and the principle of hologram generation and reconstruction,this paper combines digital hologram technology and diffraction calculation theory to explain the requirements of holographic data compression.Then,this paper studies the method of wavelet transform used in the frequency domain to compress the holograms.The methods of wavelet decomposition,threshold,quantization in frequency domain and coding in space domain are used to the holograms generated by simulation.The settings of various parameters are determined.Then,the best parameters are selected to compress and code the actual digital hologram.Finally,the results are compared and analyzed.Finally,a compression method for color digital holograms using wavelet transform and second quantization is proposed,which effectively implements hologram compression with large compression ratios.In addition,this method uses the way of cutting different color components of the hologram in proportion,so as to avoid problems such as color aliasing and position shift in the compressed reconstructed image.And this method can realize encoding and decoding in a relatively short time,while the qualit y loss of the reconstructed image is very small.