How to find mean line of the this edge?

Hi,

I'm working on image processing so i need help here i uploaded my image here.What i need is to find the middle line which will the skeleton of the edge.Please help me.

Thanks.

[KALYAN ACHARJYA]

mean line means?

Answer 1

[Matt J]

Try bwskel

Answer 2

[Image Analyst]

Call bwareafilt() to get the largest blob:

mask = bwareafilt(mask, 1);

Then scan across column by column to get the midline

[rows, columns] = size(mask);
topLines = zeros(1, columns);
bottomLines = zeros(1, columns);
for col = 1 : columns
    y = find(mask(:, col), 1, 'first');
    if ~isempty(y)
        topLines(col) = y
        bottomLines(col) = find(mask(:, col), 1, 'last')
    end
end
% Get midline
midLine = (topLines + bottomLines) / 2;
% Fit a line through it, if you want
goodColumns = topLines ~= 0;
x = 1:columns;
coefficients = polyfit(x(goodColumns), midLine(goodColumns), 1)
yFitted = polyval(coefficients, x);
hold on;
plot(x, yFitted, 'r-', 'LineWidth', 2);

[Image Analyst]

vikash, did it work?

[vikash kumar]

Thanks for reply me.

Yes it plot the one line in the middle of the fig,but my question was not this one.I got the edge dectation of the image now i want to convert it into one line such that it will look like same the image but in the the form of one line like i uploaded below.I did it into the photoshop.It any possibilty to get such type of line from the figure.

[Image Analyst]

What do you know? Like is the middle hump always in the same location or not? So you could use masking? Can you post the original gray scale image from which you made the edge image? (Because sometimes people just use edge detection for no reason when a simple intensity threshold would be better at segmenting the object of interest.)

[vikash kumar]

crop_from_image is crop from the ECG graph

BW after transfer into the binary

after_process i did

Edge_1 = edge(BW,'Canny');

J = bwmorph(Edge_1,'bridge');

J = bwmorph(J,'thicken');

J = im2uint16(J);

B = imgaussfilt(J);

J1 = bwmorph(BW,'skel');

J1 = im2uint16(J1);

B1 = imgaussfilt(J1);

add_image1 = (B+B1);

add_image2 = bwmorph3(add_image1,'fill');

add_image2 = edge(add_image2,'Canny');

after doing this i got the missing pixel then i got the edge of the outer pixel

then i put the algorithm for which I need the only one side of the edge but when i apply my algorithm it's showing like final_plot.fig which is not correct after i have to convert into the plot into the excel sheet means i have to convert scan image into the digital form.

problem with the fig also that the 3 vetical segment in between the line

[Image Analyst]

Darn, I was gettong all ready to help you now that I have more time, and you forgot to attach the images. Please attach the original PNG, tiff, bmp or JPG images. I can't call imread() on hte fig files.

[Image Analyst]

Oh, OK, so you don't really want to or need to do edge detection at all. All you need to do is to find the black lines, which you can do by color segmentation. So try that. Or better yet, just get the original digital signals if you can rather than trying to figure them out from a cell phone image of a strip chart.