The Research On Correction Technology Of Color Consistency For Fading Flicker In Old Films

Film is praised as the seventh art of mankind.Moreover,the old film,which is the treasure of human history,not only has its own artistic value,but also provides precious video material for people to study the social customs and humanities information at that time.However,due to film stock,preservation,playback and other factors,a large number of old films are damaged in varying degrees.It is an extremely urgent task to save and restore old films.There are many kinds of old film damage,and we only discuss the fading flicker in this thesis.In order to correct the color and keep the consistency of color,we proposed two solutions aimed at different conditions:1)The algorithm based on color transfer.We introduced color transfer in the restoration of old films for the first time,and transformed the problem of color consistency in image sequence into a problem of color style mapping between the reference frame and other frames.The method includes two key steps,first shot the sequence into several sub-sequence if necessary,and chose the reference frame in each sub-sequence.If there is no suitable one,we use a technology named color correction to generate a reference frame.And then,use color transfer to correct the global color of the sequence.2)The algorithm based on sparse and low-rank matrix.By simple color correction model,we established a sparse and low-rank matrix.The method,combined with multi frame images,includes three key steps.Firstly,we recover sparse color correspondences in the input frames to build a matrix with many missing entries.Secondly,we present a low-rank matrix factorization approach to estimate the unknown parameters of this model.Finally,we adopt a two-step strategy that divide the estimated parameters into reference frame parameters for color recovery correction and other frame parameters for color consistency correction to remove flicker.From the above,the method based on color transfer just need to take advantage of the statistical information of the image,which is simple and efficient,and is very suitable for applying in commercial restoration.The method based on sparse and lowrank matrix,which combined with multi frames to estimate correction parameters,takes the continuity of the input sequence into account.It has good repair effect and better universality,but time efficiency needs to be improved.