Research On Audio Extraction And Color Correction Of Cinematic Film

As the main carrier of early films,film was widely used before the 1990 s,during which many classic works were born.However,as a result of storage and age,the film was damaged by dust,dirt,mildew,discoloration,discoloration,blur and other kinds of damage.With the development of digital technology,the digital acquisition and digital restoration of film has become the main method to solve these problem.Aiming at the problem of sound returning and fading of film,the film digital acquisition and repair is carried out in this thesis based on the established film digital acquisition system.The main research contents are as follows:Firstly,the overall architecture of the system,the responsibilities of each component and the communication interface between components are described.It focuses on the analysis of the requirements of the upper computer software,and divides the functional modules based on the analysis of the requirements.Based on the function,the upper computer program is written,which enables users to complete the automatic frame by frame acquisition,audio extraction,color correction and other work by operating the UI interface.Subsequently,the automatic acquisition of film is realized by using the method of inter frame positioning.This method uses the area array camera to collect the film frame by frame,which changes the line by line scanning method used by the existing film scanning equipment.Thus,the requirement of mechanical accuracy caused by progressive scanning is reducedThen,based on the recording and playing principle of film,the image data obtained by industrial camera is transformed into digital audio by super Gaussian curve fitting method.Aiming at the problem of the high DC component of the restored sound,the method of simulating RC circuit by software is used to filter the 0 ? 63 Hz spectrum component;Taking advantage of the fact that two sound tracks carry the same sound information,the spectrum subtraction of two sections of sound is taken as the noise spectrum,and the spectrum subtraction method is used to reduce the noise of the sound signal,so as to further improve the quality of the sound signal.Finally,aiming at the problem of aging and fading of film,the imaging principle,fading mechanism and reddening reason of film are analyzed.A nonlinear fading model based on Lambert Beer's law and the transmittance of emulsion layer is established.The quantitative analysis of the relationship between the transmittance of film before and after fading is carried out.A color correction algorithm based on the fading model is proposed to correct the transmittance of each emulsion layer.Compared with the linear color correction model,this method can solve the overall reddening phenomenon while retaining the details of the image,and the correction effect is subjectively satisfactory.Experiments on several scenes show that this method can alleviate the phenomenon of film fading and restore the original color of film.