# Is poly2mask taking too much of the time?

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I am working on a dataset which consists of 1000 binary images. Following things are needed to be done for every single images: 1. Make all images to vertically align(if any of them are already vertically align then leave as it is) 2. Draw 8 circles with different radius values 3. Store each circle perimeter pixel to a profile. I have tried doing this. For storing perimeter pixel values I have used poly2mask and have considered its boundary. But this is taking too much of the time. Program is going extremely extremely slow. Unable to get outputs. Only using few data I am able to check. For 1000 data I waited for a whole day still not getting my desired output. Please anyone help me in doing this.

clc;

close all;

clear;

workspace;

folder = 'D:\data_set';

filepattern = fullfile(folder, 'P*.png');

directoryInfo = dir(filepattern);

numImages = length(directoryInfo);

for k = 1 : numImages

baseFileName = directoryInfo(k).name;

fullFileName = fullfile(folder, baseFileName);

a = imread(fullFileName);

bwimg =bwareafilt(~a, 1);

s=regionprops(bwimg,'Centroid','Orientation','MajorAxisLength','MinorAxisLength');

theta=s.Orientation;

if theta>=0 && theta<90

phi=90-theta;

y=imrotate(bwimg,phi);

else

phi=90+theta;

y=imrotate(bwimg,-phi);

end

circleCenterX =s.Centroid(1);

circleCenterY =s.Centroid(2);

diameters = mean([s.MajorAxisLength s.MinorAxisLength],2);

r1 =diameters/2;

r2=diameters/3;

r3=diameters/4;

r4=diameters/5;

r5=0.6*diameters;

r6=0.7*diameters;

r7=0.8*diameters;

r8=0.9*diameters;

radii(k,:)=[r1, r2, r3, r4,r5, r6, r7, r8];

[m,n]=size(radii);

t=0:0.001:2*pi;

for i=1:m

for j=1:n

x = circleCenterX + radii(i,j) * sin(t);

y = circleCenterY + radii(i,j) * cos(t);

bw = poly2mask(x,y,256,256);

end

end

end

end

##### 0 Comments

### Answers (1)

Image Analyst
on 16 Sep 2018

Not sure what this code does with making increasingly large circles, but this seems to work:

clc; % Clear the command window.

clearvars;

close all; % Close all figures (except those of imtool.)

workspace; % Make sure the workspace panel is showing.

format long g;

format compact;

fontSize = 20;

clc;

close all;

clear;

workspace;

folder = pwd; % 'D:\data_set';

filepattern = fullfile(folder, '*.png');

directoryInfo = dir(filepattern);

numImages = length(directoryInfo);

t=linspace(0, 2*pi, 720);

for k = 1 : numImages

baseFileName = directoryInfo(k).name;

fullFileName = fullfile(folder, baseFileName)

rgbImage = imread(fullFileName);

% Get the dimensions of the image.

% numberOfColorChannels should be = 1 for a gray scale image, and 3 for an RGB color image.

[rows, columns, numberOfColorChannels] = size(rgbImage)

if numberOfColorChannels > 1

% It's not really gray scale like we expected - it's color.

% Use weighted sum of ALL channels to create a gray scale image.

% grayImage = rgb2gray(rgbImage);

% ALTERNATE METHOD: Convert it to gray scale by taking only the green channel,

% which in a typical snapshot will be the least noisy channel.

grayImage = rgbImage(:, :, 1); % Take red channel.

else

grayImage = rgbImage; % It's already gray scale.

end

subplot(2, 2, 1);

imshow(grayImage);

title(baseFileName, 'Interpreter', 'none');

% Enlarge figure to full screen.

set(gcf, 'Units', 'Normalized', 'OuterPosition', [0, 0.04, 1, 0.96]);

drawnow;

% Now it's gray scale with range of 0 to 255.

binaryImage =bwareafilt(~grayImage, 1);

subplot(2, 2, 2);

imshow(binaryImage);

title('Binary Image', 'Interpreter', 'none');

drawnow;

s=regionprops(binaryImage,'Centroid','Orientation','MajorAxisLength','MinorAxisLength');

if isempty(s)

% Skip this image if there are no blobs.

continue;

end

theta=s.Orientation;

if theta>=0 && theta<90

phi=90-theta;

y=imrotate(binaryImage,phi);

else

phi=90+theta;

y=imrotate(binaryImage,-phi);

end

circleCenterX =s.Centroid(1);

circleCenterY =s.Centroid(2);

diameters = mean([s.MajorAxisLength, s.MinorAxisLength],2)

r1 =diameters/2;

r2=diameters/3;

r3=diameters/4;

r4=diameters/5;

r5=0.6*diameters;

r6=0.7*diameters;

r7=0.8*diameters;

r8=0.9*diameters;

radii(k,:)=[r1, r2, r3, r4, r5, r6, r7, r8];

[rowsR, colsR]=size(radii);

bw = false(rows, columns);

for j=1:colsR

thisRadius = radii(1, j);

x = circleCenterX + thisRadius * sin(t);

y = circleCenterY + thisRadius * cos(t);

bw = bw | poly2mask(x, y, rows, columns);

subplot(2, 2, 3);

imshow(bw);

caption = sprintf('Radius = %.3f', thisRadius);

title(caption);

drawnow;

end

if k < numImages

promptMessage = sprintf('Do you want to Continue processing,\nor Quit processing?');

titleBarCaption = 'Continue?';

buttonText = questdlg(promptMessage, titleBarCaption, 'Continue', 'Quit', 'Continue');

if contains(buttonText, 'Quit')

break;

end

end

end

msgbox('Done!');

##### 7 Comments

Image Analyst
on 17 Sep 2018

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