how to change video gradient to improve edge detection

Hi All,

Could you please give me a hand! I am currently writing up some cell analysis code that looks at a cell's radius and see's its change in size over time. At the moment I have gotten the edge detection software working fine but the video seems to be picking up uncessesary noise and I would really like to improve the image quality beofre I move to the next stage.

This is my code for the edge detection:

%% vidobj is input VidioReader Object
vidobj = VideoReader('VID00126.AVI');
numframes = get(vidobj, 'NumberOfFrames');
 %% finalvid is output VideoWriter Object
finalvid = VideoWriter('edgedetVID00126.avi');
finalvid.FrameRate = vidobj.FrameRate;
open(finalvid);

c = 1;
for ii = 1 : 17
    if rem(numframes,ii) == 0
        if c < ii
            c = ii;
        end
        if c == 1
            c = 10;
        end
    end
end
startframe = 1;                
stopframe = c;                       

while (stopframe <= numframes)
    frames = read(vidobj, [startframe stopframe]); 
   for l = 1:size(frames,4)
        temp = frames(:,:,:,l);
        temp = rgb2gray(temp);
        detectedge = edge(temp, 'canny');
        detectedge = single(detectedge);
        writeVideo(finalvid, detectedge);
    end
    startframe = startframe + c;
    stopframe = stopframe + c;
end

close(finalvid);

I have been trying to use the following link's code to change the gradient but it only seems to be working for images, could anyone tell me what I could do?

https://uk.mathworks.com/help/images/ref/imgradient.html

Thanks in advance everyone.

Ben

[darova]

Attach the data

[Ben Timm]

Heya,

Apologies, I'm very much a beginner. Attach it in what way? A datastore?

Thanks again,

[darova]

Do you have small example video?

[Ben Timm]

Frustratingly the file is too large to share on this. Is there another way I could send it to you?

[darova]

• At the moment I have gotten the edge detection software working fine but the video seems to be picking up uncessesary noise

You think it happens during writing video? You have good quality in MATLAB?

[Ben Timm]

Best I can do is screenshot! You can see the edge detection working but its got a tonne of uncessesary lines and ideally id like to clean up the image.

Answer 1

[darova]

Try this

I0 = imread('Screenshot 2020-04-09 at 15.50.08.png');

I1 = im2bw(I0,graythresh(I0)-0.03); % binarize image with treshold
I2 = bwareaopen(I1,50);             % remove small regions (50 pixels)
I3 = edge(I2);

II = imfuse(I0,I3);
imshow(II)

Looks like something simple but im not good at this

There is another person who specializes on this. But i don't like him

[Ben Timm]

Hi Darova,

Sorry for not getting back to you quickly, it was due to medical reasons. This is interesting! I tried applying it to a video though and it wouldnt work (see attached) when I changed it to implay.

Thats perfectly fine and understandable, I doubt many use the code for this application. Would you happen to know their name so I can contact them as well?

Thanks again as usual :)

[darova]

Use this to read video

v = VideoReader('xylophone.mp4');
n = v.NumberOfFrames;
for i = 1:n
    I0 = read(v,i);
%     I0 = imread('Screenshot 2020-04-09 at 15.50.08.png');
    I1 = im2bw(I0,graythresh(I0)-0.03); % binarize image with treshold
    I2 = bwareaopen(I1,50);             % remove small regions (50 pixels)
    I3 = edge(I2);

    II = imfuse(I0,I3);
    imshow(II,'initialmagnification','fit')
    pause(0.1)
end

• Would you happen to know their name so I can contact them as well?

Sure, here is he: Image Analyst