MATLAB随手记

MATLAB随手记

1. 读写文件

简单读写

fp = fopen('record.txt', 'r');

while ~feof(fp) % 只要没读完

    line = fgetl(fp); % 读下一行

    if contains(line, 'Hello')

        pass

    end

end

将rgb保存为yuv文件

%mov2yuv creates a Matlab-Movie from a YUV-File.

%	mov2yuv('Filename',mov, format) writes the specified file

%	using format for YUV-subsampling.

%

%	Filename --> Name of File (e.g. 'Test.yuv')

%   mov      --> Matlab-Movie

%   format   --> subsampling rate ('400','411','420','422' or '444')

%

%example: mov2yuv('Test.yuv',mov,'420');

function mov2yuv(File,mov,format)

    %set factor for UV-sampling

    fwidth = 0.5;

    fheight= 0.5;

    if strcmp(format,'400')

        fwidth = 0;

        fheight= 0;

    elseif strcmp(format,'411')

        fwidth = 0.25;

        fheight= 1;

    elseif strcmp(format,'420')

        fwidth = 0.5;

        fheight= 0.5;

    elseif strcmp(format,'422')

        fwidth = 0.5;

        fheight= 1;

    elseif strcmp(format,'444')

        fwidth = 1;

        fheight= 1;

    else

        display('Error: wrong format');

    end

    %get Resolution and Framenumber

    resolution = size(mov(1).cdata);

    framenumber = size(mov);

    framenumber = framenumber(2);

    fclose(fopen(File,'w')); %Init File

    h = waitbar(0,'Please wait ... ');

    %write YUV-Frames

    for cntf = 1:1:framenumber

        waitbar(cntf/framenumber,h);

        YUV = rgb2ycbcr(mov(cntf).cdata);

        save_yuv(YUV,File,resolution(2),resolution(1),fheight,fwidth);

    end

    close(h);

%Save YUV-Data to File

function save_yuv(data,video_file,BreiteV,HoeheV,HoehenteilerV,BreitenteilerV)

    %get Resolution od Data

    datasize = size(data);

    datasizelength = length(datasize);

    %open File

    fid = fopen(video_file,'a');

    %subsampling of U and V

    if datasizelength == 2 | HoehenteilerV == 0

        %4:0:0

        y(1:HoeheV,1:BreiteV) = data(:,:,1);

    elseif datasizelength == 3

        y(1:HoeheV,1:BreiteV) = double(data(:,:,1));

        u(1:HoeheV,1:BreiteV) = double(data(:,:,2));

        v(1:HoeheV,1:BreiteV) = double(data(:,:,3));

        if BreitenteilerV == 1

            %4:1:1

            u2 = u;

            v2 = v;

        elseif HoehenteilerV == 0.5

            %4:2:0

            u2(1:HoeheV/2,1:BreiteV/2) = u(1:2:end,1:2:end)+u(2:2:end,1:2:end)+u(1:2:end,2:2:end)+u(2:2:end,2:2:end);

            u2                         = u2/4;

            v2(1:HoeheV/2,1:BreiteV/2) = v(1:2:end,1:2:end)+v(2:2:end,1:2:end)+v(1:2:end,2:2:end)+v(2:2:end,2:2:end);

            v2                         = v2/4;

        elseif BreitenteilerV == 0.25

            %4:1:1

            u2(1:HoeheV,1:BreiteV/4) = u(:,1:4:end)+u(:,2:4:end)+u(:,3:4:end)+u(:,4:4:end);

            u2                       = u2/4;

            v2(1:HoeheV,1:BreiteV/4) = v(:,1:4:end)+v(:,2:4:end)+v(:,3:4:end)+v(:,4:4:end);

            v2                       = v2/4;

        elseif BreitenteilerV == 0.5 & HoehenteilerV == 1

            %4:2:2

            u2(1:HoeheV,1:BreiteV/2) = u(:,1:2:end)+u(:,2:2:end);

            u2                       = u2/2;

            v2(1:HoeheV,1:BreiteV/2) = v(:,1:2:end)+v(:,2:2:end);

            v2                       = v2/2;

        end

    end

    fwrite(fid,uint8(y'),'uchar'); %writes Y-Data

    if HoehenteilerV ~= 0

        %writes U- and V-Data if no 4:0:0 format

        fwrite(fid,uint8(u2'),'uchar');

        fwrite(fid,uint8(v2'),'uchar');

    end

    fclose(fid);

从yuv文件中读取Y通道

function [y] = y_import(filename,dims,range_frames,yuvformat)

% Import Y channel from a yuv video.

% dims: [width, height]

% range_frames: 1:nf

% return: a cell (nfs * height * width)

%% Read yuv

fid=fopen(filename,'r');

if (fid < 0)

    error('File does not exist!');

end

%% Fill up default

if (nargin < 4)

    yuvformat = 'YUV420_8';

end

%% Calculate inprec and sampl

inprec = 'ubit8';

sampl = 420;

if (strcmp(yuvformat,'YUV420_16'))

    inprec = 'uint16'; %'ubit16=>uint16'

elseif (strcmp(yuvformat,'YUV444_8'))

    sampl = 444;

end

%% Calculate frelem

if (sampl == 420)

    dimsUV = dims / 2;

else

    dimsUV = dims;

end

Yd = zeros(dims(1),dims(2));

frelem = numel(Yd) + 2 * dimsUV(1) * dimsUV(2);

%% extraction

num_frames = length(range_frames);

y = cell(1,num_frames);

for ite_frame = 1:num_frames

    startfrm = range_frames(ite_frame) - 1; % the first frame start from 0 frame.

    fseek(fid, startfrm * frelem , -1); % go to the starting frame

    Yd = fread(fid,dims,inprec);

    y{ite_frame} = Yd'; % height * width

end

fclose(fid);

return

将TIFF图片拼接为yuv文件

dir_img = "G:\SCI\Database\RAISE_8k";

image_list = dir(fullfile(dir_img, "*.TIF"));

image_list = {image_list.name}';

num_image = length(image_list);

random_order = randperm(num_image); % randperm(N)将会使得[1 2 ... N]序列打乱并返回该行向量。

index_list_tra = random_order(1:4900);

index_list_val = random_order(4900+1:4900+1628);

index_list_test = random_order(4900+1628+1:8156);

tar_w = 1920;

tar_h = 1080;

dir_store = ".\Database";

%% Training set

filename = "RAISE-8156_raw_1920x1080_4900_tra.yuv";

fid= fopen(fullfile(dir_store, filename),'w');

nfs = length(index_list_tra);

for i = 1:nfs

    disp(string(i) + " | " + string(nfs));

    index = index_list_tra(i);

    img = Tiff(fullfile(dir_img, image_list(index)),'r');

    img = read(img);

    YUVimg = rgb2ycbcr(img);

    %imshow(YUVimg)

    [imgHeight imgWidth imgDim] = size(YUVimg);

    Y = YUVimg(imgHeight/2-(tar_h/2-1):imgHeight/2+tar_h/2,imgWidth/2-(tar_w/2-1):imgWidth/2+tar_w/2,1);     % Y 矩阵  % Cut to 832x480

    U = YUVimg(imgHeight/2-(tar_h/2-1):imgHeight/2+tar_h/2,imgWidth/2-(tar_w/2-1):imgWidth/2+tar_w/2,2);     % U 矩阵

    V = YUVimg(imgHeight/2-(tar_h/2-1):imgHeight/2+tar_h/2,imgWidth/2-(tar_w/2-1):imgWidth/2+tar_w/2,3);     % V 矩阵

    [imgHeight imgWidth] = size(Y);

    y = double(Y);

    u = double(U);

    v = double(V);

    u2(1:imgHeight/2,1:imgWidth/2) = u(1:2:end,1:2:end)+u(2:2:end,1:2:end)+u(1:2:end,2:2:end)+u(2:2:end,2:2:end);

    u2                         = u2/4;

    v2(1:imgHeight/2,1:imgWidth/2) = v(1:2:end,1:2:end)+v(2:2:end,1:2:end)+v(1:2:end,2:2:end)+v(2:2:end,2:2:end);

    v2                         = v2/4;

    %imshow(Y);

    %fwrite(fid,yuv420out,'uint8');

    fwrite(fid,uint8(y'),'uchar');

    fwrite(fid,uint8(u2'),'uchar');

    fwrite(fid,uint8(v2'),'uchar');

end

fclose(fid);

2. 字符串操作

pos = strfind(str_t, "Hello")：会返回所有搜寻到的Hello的首字母位置。
num = str2double(str_t)

3. 画图

依次图例：legend(["a","b","c"])

巴特西

Note | MATLAB

MATLAB随手记

1. 读写文件

简单读写

将rgb保存为yuv文件

从yuv文件中读取Y通道

将TIFF图片拼接为yuv文件

2. 字符串操作

3. 画图

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