How to store SURF features of multiple images

Question

KDR 2017-1-12

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/320080-how-to-store-surf-features-of-multiple-images

评论： lebed toufik 2022-2-19

Hello all, I'm using SURF descriptor for feature extraction from folder of images. The result i.e. surf features are of different dimension for different image i.e. N*64, N varies with each image. These features are to be classified using knn classifier,one image with all of its features as one class. But KNN classifier takes each row wise features as one class. So how to classify this varying row size features or how to store this in a format that is passed as input to KNN classifier. Below is the code where "features1{i}" contains all the surf features.

srcFiles = dir('C:\Users\nmamit\Documents\MATLAB\photos\*.jpg');  % the folder in which ur images exists
for i = 1 : length(srcFiles)
   filename = strcat('C:\Users\nmamit\Documents\MATLAB\photos\',srcFiles(i).name);
   I1 = rgb2gray(imread(filename));
      points1 = detectSURFFeatures(I1); 
   feature = zeros(1, length(srcFiles))
   [features1{i}, valid_points1{i}] = extractFeatures(I1, points1); 
   figure; imshow(I1);hold on;
   plot(valid_points1{i}.selectStrongest(10),'showOrientation',true);
end

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KS 2017-8-14

Hi, I am having the same problem. Can you please tell me if you came up with a solution?

Thanks.

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Answer 1

KSSV 2017-1-12

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/320080-how-to-store-surf-features-of-multiple-images#answer_250297

在 MATLAB Online 中打开

Store them into cells.

srcFiles = dir('C:\Users\nmamit\Documents\MATLAB\photos\*.jpg');  % the folder in which ur images exists
Features = cell(length(srcFiles),1) ;
Valid_points = cell(length(srcFiles),1) ;
for i = 1 : length(srcFiles)
    filename = strcat('C:\Users\nmamit\Documents\MATLAB\photos\',srcFiles(i).name);
    I1 = rgb2gray(imread(filename));
    points1 = detectSURFFeatures(I1);
    [features1, valid_points1] = extractFeatures(I1, points1);
    Features{i} = features1 ;
    Valid_points{i} = valid_points1 ;
    figure; imshow(I1);hold on;
    plot(valid_points1{i}.selectStrongest(10),'showOrientation',true);
end
Features
Valid_points