Question

我想在videoframes上使用rgb2gray转换视频文件，事情是我不完全确定如何。

我有这个脚本文件，使用滑块播放视频文件：

％---------------------------------------------- ---------------------

function frametracking()
%# read all frames at once
filename = uigetfile('*.avi');
vid = VideoReader(filename);
numImgs = get(vid, 'NumberOfFrames');
frames = read(vid);

% Make the UI    
mx = numImgs-1;
hFig = figure('Menubar','none');
uicontrol('Style','slider', 'Parent',hFig, ...
    'Callback',@slider_callback, ...
    'Units','pixels', 'Position',[150 0 260 20], ...
    'Value',1, 'Min',1, 'Max',mx, 'SliderStep',[1 10]./mx);
pB1 = uicontrol(hFig, 'Position',[150 20 130 20], ...
    'Units','pixels', ...
    'String','Select file', ...
    'Callback',@button1_callback);
pB2 = uicontrol(hFig, 'Position',[280 20 130 20], ...
    'Units','pixels', ...
    'String','Calibrate', ...
    'Callback',@button2_callback);
eT1 = uicontrol(hFig, 'Style','edit',...
    'Units','pixels',...
    'Position',[490 400 60 20],...
    'CallBack',@edit1_callback,...
    'String','');
eT2 = uicontrol(hFig, 'Style','edit',...
    'Units','pixels',...
    'Position',[490 370 60 20],...
    'CallBack',@edit2_callback,...
    'String','');
eT3 = uicontrol(hFig, 'Style','edit',...
    'Units','pixels',...
    'Position',[490 370 60 20],...
    'CallBack',@edit3_callback,...
    'String','');
hAx = axes('Parent',hFig,'units','pixels',...
    'Position',[80 80 400 400]);
grayframe = rgb2gray(frames(:,:,:,1));
hMainImg = imshow(grayframe(:,:,:,1), 'Parent',hAx);

%# callback functions
    function slider_callback(src,~)
        val = round(get(src,'Value'));  %# starting index
        %# update the thumbnails
        for ii = 1 : numel(hMainImg)
            set(hMainImg(ii), 'CData',frames(:,:,:,ii+val-1))
            drawnow
        end
    end

    function click_callback(src,~)
        %# update the main image
      %  grayframe = rgb2gray(frames(:,:,:,1));
        set(hMainImg, 'CData',get(src,'CData'));
        drawnow
    end

    function button1_callback(src,~)

    end
end

％---------------------------------------------- ---------------------

在第40行，我添加了：grayframe = rgb2gray（frames（：，：，：，1））;,这使第一帧变为灰色。如何对所有帧进行计数？我的目标是跟踪视频帧中的对象，因此我想将帧转换为二进制图像，并应用额外的过滤器，如边缘检测或类似的东西。

提前致谢

Answer 1

for i=1:numImgs
  frames(:,:,:,i)=rgb2gray(frames(:,:,:,i));
end

Answer 2

我宁愿摆脱rgb2gray并将其矢量化

GRAYframes = uint8(mean(RGBframes,3));

Answer 3

1-构建一个VideoReader对象

2-读取每个帧并使用RGB2GRAY将其转换为灰度

3-播放视频

clear
clc
obj = VideoReader('xylophone.mp4');
nFrames = obj.NumberOfFrames;
vidHeight = obj.Height;
vidWidth = obj.Width;
mov(1:nFrames) =struct('cdata',zeros(vidHeight,vidWidth,1,'uint8'),...
    'colormap',[]);
% Read one frame at a time. 
for k = 1 : nFrames
    mov(k).cdata =rgb2gray( read(obj,k));
end
implay(mov);

将rgb-video输入转换为灰度输出

3 个答案: