How to use the edge function to extract a curve from the photo, and then draw this curve on the coordinate system, and finally smooth the curve.

How to use the edge function to extract a curve from the photo, and then draw this curve on the coordinate system, and finally smooth the curve.I am very grateful to everyone for helping me solve this problem.

[KALYAN ACHARJYA]

Please attach the sample photo.

[Wesley]

The picture I uploaded is like this, please help me to see if I can use the program to extract the curve.

[KALYAN ACHARJYA]

Wen's comments (Image) as an answer has been deleted. Same Image in Attached.

[Wesley]

Yes, indeed.

Answer 1

[KALYAN ACHARJYA]

data=imbinarize(imread('image.jpeg'));
result=edge(data);
figure,imshow(result);
[r,c]=find(result==1);
figure,plot(c,r,'.');

[KALYAN ACHARJYA]

Hope, further any improvemnet, you can do that #Keeplearning

[Wesley]

What should I do if I want to perform curve fitting further?

[Wesley]

Comparing the curve after the program is run with the curve on the original image, two problems were found. The first problem is that the curve looks flatter. The second problem is that the extracted curve is reversed compared with the original image. I hope I can continue to discuss these issues with you.

[KALYAN ACHARJYA]

"The second problem is that the extracted curve is reversed compared with the original image"

Please change in plot parameters, so do trasposen as per your desire result

plot(r,c,'.');  

In the second case, please make the plot line thicker, so that you can observe the line as per boundary white pixels presence in the image.

data=imbinarize(imread('image.jpeg'));
result=edge(data);
[r,c]=find(result==1);
plot(c,r,'.','linewidth',0.01);
grid on; 

Still, you are lokking for curve fitting, please see this documentation

[Wesley]

Using this code can not achieve the desired effect. The generated curve is shown in the figure below.

[Wesley]

Using this code can not achieve the desired effect. The generated curve is shown in the figure below.

[KALYAN ACHARJYA]

Ok, Is the problem solved?

[Wesley]

Unfortunately, I haven't solved this problem.

.

[Wesley]

I found the source of the problem. The reason is that the MATLAB software draws the line with the point in the upper left corner as the origin, so we see the image in the opposite direction to the original image.