Question

I need to detect the x-axis and y-axis on a diagram. Existing libraries for PHP cannot detect the lines as this process requires Hough Transform method (please correct me if I am wrong) Is there any way to detect the axises with/without Hough Transform using PHP.

an example to the diagram:

Answer 1

I think if the goal is the detection of the axis only, an easier approach would be using morphological operations (using hough transform could be really computationally demanding, and possibly wouldn’t work with so much “noise”). I would rather use GNU octave to do the image processing operations, than serve the results through a php frontend.

Possible code for starting could be (e.g. to detect origin and maximum values – filter for minimal x, maximal x, minimal y, maximal y to get the corners):

I = rgb2gray(imread('iEth9.jpg'));
I = I < 11;
A = imopen(I, ones(1,100)');
B = imopen(I, ones(1,100));
imagesc(I);hold on;
[y,x] = find(A&B);
plot(x,y,'ro');