can someone help me edit the code below so that the output image can display the value of rotation angle of the object with axis guide

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It is just the example image that i want, the axis with the angle:
this is my input image:
% Perform edge detection with interpolation during non maximum suppression
function CannyEdgeDetector()
close all; % Close figures
saveImage = true;
sigma = 1; % Gaussian filter sigma
highThresholdRatio = 0.275; % High threshold ratio
lowThresholdRatio = 0.25; % Low threshold ratio OF THE high threshold
% Change the current folder to the folder of this m-file.
% Courtesy of Brett Shoelson
if(~isdeployed)
cd(fileparts(which(mfilename)));
end
im = imread('C:\Users\User\Pictures\bt.jpeg');
figure; imshow(im);
title('Original Image');
%if saveImage
%imwrite(im, 'C:\Users\User\Pictures\O3.jpeg');
%end
% Smooth with Gaussian 5x5 filter to reduce noise
im = rgb2gray(im);
figure; imshow(im);
title('B/W Image');
%if saveImage
%imwrite(im, 'Output_Photos\2_bw.jpg');
%end
im = double(imgaussfilt(im,sigma));
figure; imshow(NormalizeMatrix(im));
title('Gaussian Filter');
%if saveImage
%imwrite(NormalizeMatrix(im), 'Output_Photos\3_gaussian.jpg');
%end
% Find the intensity gradient of the image
Gx = SobelFilter(im, 'x');
Gy = SobelFilter(im, 'y');
Gx = imgaussfilt(Gx,sigma);
Gy = imgaussfilt(Gy,sigma);
figure; imshow(abs(normalize(Gx)));
title('Gx Sobel Filter');
%if saveImage
%imwrite(abs(NormalizeMatrix(Gx)), 'Output_Photos\4_gx_sobel.jpg');
%end
figure; imshow(abs(NormalizeMatrix(Gy)));
title('Gy Sobel Filter');
%if saveImage
%imwrite(abs(NormalizeMatrix(Gy)), 'Output_Photos\5_gy_sobel.jpg');
%end
% Find the magnitude of the gradient
Gmag = sqrt(Gx.^2 + Gy.^2);
angle = atan2(Gy,Gx)*180/pi;
figure; imshow(NormalizeMatrix(Gmag));
title('Gmag');
%if saveImage
%imwrite(NormalizeMatrix(Gmag), 'Output_Photos\6_gmag.jpg');
%end
% Perform non-maximum suppression using interpolation
[h,w] = size(im);
X=[-1,0,+1 ;-1,0,+1 ;-1,0,+1];
Y=[-1,-1,-1 ;0,0,0 ;+1,+1,+1];
output = zeros(h,w);
x = [0 1];
for i=2:h-1 % row
for j=2:w-1 % col
if (angle(i,j)>=0 && angle(i,j)<=45) || ...
(angle(i,j)<-135 && angle(i,j)>=-180)
yBot = [Gmag(i,j+1) Gmag(i+1,j+1)];
yTop = [Gmag(i,j-1) Gmag(i-1,j-1)];
x_est = abs(Gy(i,j)/Gmag(i,j)); % y
if (Gmag(i,j) >= ((yBot(2)-yBot(1))*x_est+yBot(1)) && ...
Gmag(i,j) >= ((yTop(2)-yTop(1))*x_est+yTop(1))) % interpolation
output(i,j)= Gmag(i,j);
else
output(i,j)=0;
end
elseif (angle(i,j)>45 && angle(i,j)<=90) || ...
(angle(i,j)<-90 && angle(i,j)>=-135)
yBot = [Gmag(i+1,j) Gmag(i+1,j+1)];
yTop = [Gmag(i-1,j) Gmag(i-1,j-1)];
x_est = abs(Gx(i,j)/Gmag(i,j));
if (Gmag(i,j) >= ((yBot(2)-yBot(1))*x_est+yBot(1)) && ...
Gmag(i,j) >= ((yTop(2)-yTop(1))*x_est+yTop(1)))
output(i,j)= Gmag(i,j);
else
output(i,j)=0;
end
elseif (angle(i,j)>90 && angle(i,j)<=135) || ...
(angle(i,j)<-45 && angle(i,j)>=-90)
yBot = [Gmag(i+1,j) Gmag(i+1,j-1)];
yTop = [Gmag(i-1,j) Gmag(i-1,j+1)];
x_est = abs(Gx(i,j)/Gmag(i,j));
if (Gmag(i,j) >= ((yBot(2)-yBot(1))*x_est+yBot(1)) && ...
Gmag(i,j) >= ((yTop(2)-yTop(1))*x_est+yTop(1)))
output(i,j)= Gmag(i,j);
else
output(i,j)=0;
end
elseif (angle(i,j)>135 && angle(i,j)<=180) || ...
(angle(i,j)<0 && angle(i,j)>=-45)
yBot = [Gmag(i,j-1) Gmag(i+1,j-1)];
yTop = [Gmag(i,j+1) Gmag(i-1,j+1)];
x_est = abs(Gx(i,j)/Gmag(i,j));
if (Gmag(i,j) >= ((yBot(2)-yBot(1))*x_est+yBot(1)) && ...
Gmag(i,j) >= ((yTop(2)-yTop(1))*x_est+yTop(1)))
output(i,j)= Gmag(i,j);
else
output(i,j)=0;
end
end
end
end
Gmag = NormalizeMatrix(output);
figure; imshow(Gmag);
title('Non Maximum Suppression');
%if saveImage
%imwrite(Gmag, 'Output_Photos\7_non_maximum_suppression.jpg');
%end
% Perform double thresholding
highThreshold = max(max(Gmag))*highThresholdRatio;
lowThreshold = highThreshold*lowThresholdRatio;
strongEdgesRow = zeros(1,h*w); % Keep track of the strong edge row index
strongEdgesCol = zeros(1,h*w); % Keep track of the strong edge col index
weakEdgesRow = zeros(1,h*w); % Keep track of the weak edge row index
weakEdgesCol = zeros(1,h*w); % Keep track of the weak edge col index
strongIndex = 1;
weakIndex = 1;
for i=2:h-1 % row
for j=2:w-1 % col
if Gmag(i,j) > highThreshold % Strong edge
Gmag(i,j) = 1;
strongEdgesRow(strongIndex) = i;
strongEdgesCol(strongIndex) = j;
strongIndex = strongIndex + 1;
elseif Gmag(i,j) < lowThreshold % No edge
Gmag(i,j) = 0;
else % Weak edge
weakEdgesRow(weakIndex) = i;
weakEdgesCol(weakIndex) = j;
weakIndex = weakIndex + 1;
end
end
end
figure; imshow(Gmag);
title('Double Threshold');
%if saveImage
%imwrite(Gmag, 'Output_Photos\8_double_threshold.jpg');
%end
% Perform edge tracking by hysteresis
set(0,'RecursionLimit',10000)
for i=1:strongIndex-1
% Find the weak edges that are connected to strong edges and set
% them to 1
Gmag = FindConnectedWeakEdges(Gmag, strongEdgesRow(i),...
strongEdgesCol(i));
end
figure; imshow(Gmag);
title('Edge Tracking Before Clean Up');
%if saveImage
%imwrite(Gmag, 'Output_Photos\9_edge_tracking.jpg');
%end
% Remove the remaining weak edges that are not actually edges
% and is noise instead
for i=1:weakIndex-1
if Gmag(weakEdgesRow(i),weakEdgesCol(i)) ~= 1
Gmag(weakEdgesRow(i),weakEdgesCol(i)) = 0;
end
end
figure; imshow(Gmag);
title('Edge Tracking After Clean Up');
%if saveImage
%imwrite(Gmag, 'Output_Photos\10_final.jpg');
%end
% % MATLAB canny comparison
% im = imread('Test_Photos/test1.jpg');
% im = rgb2gray(im);
% im = edge(im, 'canny');
% figure; imshow(im);
% title('MATLAB');
end
% Normalize matrix
function[A] = NormalizeMatrix(A)
A = A/max(A(:));
end
% Perform sobel filter
function[A] = SobelFilter(A, filterDirection)
switch filterDirection
case 'x'
Gx = [-1 0 +1; -2 0 +2; -1 0 +1];
A = imfilter(A, double(Gx), 'conv', 'replicate');
case 'y'
Gy = [-1 -2 -1; 0 0 0; +1 +2 +1];
A = imfilter(A, double(Gy), 'conv', 'replicate');
otherwise
error('Bad filter direction - try inputs ''x'' or ''y''');
end
end
% Find weak edges that are connected to strong edges and set them to 1
function[Gmag] = FindConnectedWeakEdges(Gmag, row, col)
for i = -3:1:3
for j = -3:1:3
if (row+i > 0) && (col+j > 0) && (row+i < size(Gmag,1)) && ...
(col+j < size(Gmag,2)) % Make sure we are not out of bounds
if (Gmag(row+i,col+j) > 0) && (Gmag(row+i,col+j) < 1)
Gmag(row+i,col+j) = 1;
Gmag = FindConnectedWeakEdges(Gmag, row+i, col+j);
end
end
end
end
end

Answers (2)

yanqi liu
yanqi liu on 20 May 2022
yes,sir,may be use minboundrect to get the rect area,such as

Image Analyst
Image Analyst on 21 May 2022
I'd use bwferet and get the min angle. Let me know if you can't figure it out.
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