Hello, I am looking for advice on image analyzing on covid strip tests in order to see if tests are positive or negative (two or one horizontal lines).

Hello, I am trying to detect if an image has parallel horizontal lines using matlab (meaning test strip indicates positive). I have tried many different Matlab image functions, but have been unsuccessful thus far. An example could be processing the below image to see that the first strip has one line, the second strip has two lines, and the third strip has one line. Here is the code I have tried using thus far:

image = imread("MultiplexV1Negativetests.jpeg","jpeg");
previousimage = image;
gray_img = rgb2gray(image);
% Use global thresholding to convert the image to binary
threshold = graythresh(gray_img);   
binary_img = im2bw(gray_img, threshold);
% Invert the binary image
binary_img = ~binary_img;
% Multiply the binary image with the original image to remove the background
image(repmat(~binary_img,[1 1 3])) = 0;
figure(1)
subplot(1,2,1)
imshow(previousimage)
subplot(1,2,2)
imshow(image)
B=im2gray(image);
figure(2)
imshow(B)
B2=im2double(B);
BW = edge(B2,'canny');
figure(3)
imshow(BW)
figure(4)
[H,T,R] = hough(BW);
imshow(H,[],'XData',T,'YData',R,...
    'InitialMagnification','fit');
xlabel('\theta'), ylabel('\rho');
axis on, axis normal, hold on;
P  = houghpeaks(H,5,'threshold',ceil(0.3*max(H(:))));
x = T(P(:,2)); y = R(P(:,1));
plot(x,y,'s','color','white');
c = numel(find(x==0))

Any advice for new functions/techniques to try to implement would be greatly appreciated. Thank you!

Answer 1

[Cris LaPierre]

I'd suggest the following courses

• Image Processing Onramp
• Image Processing for Engineering and Science