Interpolation filter in video

Question

Alber 2020-3-9

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/509835-interpolation-filter-in-video

评论： Ameer Hamza 2020-3-9

Hello,

I've been looking at the documentation on the 'interp' function, which is the function that I think I should use.

My problem is as follows: I have two types of images, alpha and negative alpha, which is alpha * (-1). Imagine that my alpha image goes from 1 to -1 and the negative alpha goes from -1 to 1, what I want to achieve is to create a video of numbers of Frames 'N', where the interpolation values are parameterizable, that is the interpolation time and the number of samples to be used, thus achieving a 'temporary' filtering.

The result of this function should be a 'N' frames video where what we will see will be in frame1: alpha, ...... frame3: alpha negative, .... frame5: alpha, frame7: alpha negative .. ..

Frame 3 is an example since it will depend on interpolation.

In the following image I show you an example of what it should be, to see if you can guide me or give a help with this problem.

Thank you very much in advance, any sure answer will help me, regards!

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Answer 1

Ameer Hamza 2020-3-9

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https://ww2.mathworks.cn/matlabcentral/answers/509835-interpolation-filter-in-video#answer_419223

在 MATLAB Online 中打开

I am not sure why you scaled the pixels from -1 to 1. The following code use pixel values from 0 to 1, and the inverse image have pixel values from 1 to 0.

im = im2double(imread('peacock.jpg'));
im_reverse = 1-im;
N = 10;
time = reshape(linspace(0, 1, N), 1, 1, 1, N);
frames = im_reverse.*time + im.*(1-time);
v = VideoWriter('video_file', 'MPEG-4');
v.FrameRate = 10;
open(v);
for i = 1:5 % how many times to repeat pattern
    % im to im_reverse
    for j=1:N
        frame = frames(:,:,:,j);
        writeVideo(v, frame);
    end
    % im_reverse to im
    for j=N:-1:1
        frame = frames(:,:,:,j);
        writeVideo(v, frame);
    end
end
close(v);