# Error while using PCA for image recognition?

2 vues (au cours des 30 derniers jours)
Anjana Rao le 11 Mar 2014
Commenté : suchetha n le 1 Jan 2021
Hello!
I've used this code for image recognition using PCA. I keep getting this error:
Error using -
Integers can only be combined with integers of the same class, or scalar doubles.
Error in pirnccompanal (line 43)
feature_vec = evectors' * (input_image(:) - mean_face);
----------------------------------------------------------------------------------------------
Can someone tell me what is wrong with the code? All the images used have dimensions of 60x60. gest1Cell is a cell of 30 images in grayscale (60x60).
clc;
clear all;
gestdatabase;
input_image = gest1Cell{25};
images = [];
image_dims = [60, 60];
num_images = 30;
for n = 1:30
img = gest1Cell{n};
if n == 1
images = zeros(prod(image_dims), num_images);
end
images(:, n) = img(:);
end
% TRAINING
% steps 1 and 2: find the mean image and the mean-shifted input images
mean_face = mean(images, 2);
shifted_images = images - repmat(mean_face, 1, num_images);
% steps 3 and 4: calculate the ordered eigenvectors and eigenvalues
[evectors, score, evalues] = pca(images');
% step 5: only retain the top 'num_eigenfaces' eigenvectors (i.e. the principal components)
num_eigenfaces = 20;
evectors = evectors(:, 1:num_eigenfaces);
% step 6: project the images into the subspace to generate the feature vectors
features = evectors' * shifted_images;
% TESTING AND CLASSIFICATION
% calculate the similarity of the input to each training image
feature_vec = evectors' * (input_image(:) - mean_face);
similarity_score = arrayfun(@(n) 1 / (1 + norm(features(:,n) - feature_vec)), 1:num_images);
% find the image with the highest similarity
[match_score, match_ix] = max(similarity_score);
% display the result
figure, imshow([input_image reshape(images(:,match_ix), image_dims)]);
title(sprintf('matches %s, score %f', filenames(match_ix).name, match_score));
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suchetha n le 1 Jan 2021
For calculating similarity score which method is used?

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### Réponses (1)

Image Analyst le 11 Mar 2014
Try casting everything to double before doing the math.
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