Eigenface Face Recognition: Why do I keep getting "Subscripted assignment dimension mismatch"?
显示 更早的评论
I was working on a code that I got from https://blog.cordiner.net/2010/12/02/eigenfaces-face-recognition-matlab/. I was able to make it work. Then after taking a break, I came back to the code and started getting "Subscripted assignment dimension mismatch."
Here's the code:
%%Loading the Images
clear all
close all
clc
input_dir = 'C:\Users\Nadlei\Desktop\dlsufacereg\Training';
image_dims = [30, 64];
filenames = dir(fullfile(input_dir, '*.jpg'));
num_images = 30;
images = zeros(prod(image_dims),num_images);
for n = 1:num_images
filename = fullfile(input_dir, filenames(n).name);
img = imread(filename);
%img = imresize(img,[30,64]);
img = im2double(img);
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;
% calculate the similarity of the input to each training image
input_image = imread('input.jpg');
input_image = imresize(input_image,image_dims);
input_image = im2double(input_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] = min(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));
The error occurs at: "images(:,n) = img(:);" I know that it means that the matrix assignments don't match, but how do I fix it? All my input images are already in grayscale and resized to Width:30 and Height:64. Someone please help me.
采纳的回答
Walter Roberson
2016-4-10
0 个投票
One of your images is not the same size as the others. You have an imresize() there that would take care of that problem, but you have that imresize() commented out.
5 个评论
Jess Marcos
2016-4-10
Jess Marcos
2016-4-10
Walter Roberson
2016-4-10
Change
for n = 1:num_images
filename = fullfile(input_dir, filenames(n).name);
img = imread(filename);
img = im2double(imresize(img, image_dims));
images(:, n) = img(:);
end
to
for n = 1:num_images
filename = fullfile(input_dir, filenames(n).name);
[img, map] = imread(filename);
if isempty(img)
error('Somehow file "%s" has an empty image!', filename);
end
if ~isempty(map)
error('Somehow file "%s" is a pseudocolor JPEG image, which is not possible in standard JPEG!', filename);
end
if ndims(img) > 2
img = zeros(image_dims);
warning('File "%s" was an RGB JPEG image (as nearly all JPEG images are), but the code expects it to one of the rare grayscale JPEG images. Substituting black image instead.', filename);
else
img = im2double(imresize(img, image_dims));
end
images(:, n) = img(:);
end
Jess Marcos
2016-4-10
Walter Roberson
2016-4-10
The only possibility that comes to mind is if you only had a single image then you would be sending a row vector to pca and perhaps it treats row vectors differently?
Ah, there is another explanation: your num_images might be 0, so your images variable might be empty.
Put in a breakpoint and look at the size of images and evectors and let us know what you found.
更多回答（2 个）
Neelesh Patel
2017-8-10
编辑：Walter Roberson
2017-8-10
in same code i have error occured in that line;
feature_vec = evectors' * (input_image(:) - mean_face);
**Matrix dimensions must agree.**
6 个评论
Walter Roberson
2017-8-10
input_image is not the same size as the images you trained on.
Neelesh Patel
2017-8-10
编辑：Walter Roberson
2017-8-10
hello sir i m trying to execute this code:
%%Loading the Images
input_dir ='E:\TARGET FOLDER';
image_dims = [64, 30];
filenames = dir(fullfile(input_dir, '*.jpg'));
num_images = numel(filenames);
images = zeros(prod(image_dims), num_images);
for n = 1:num_images
filename = fullfile(input_dir, filenames(n).name);
[img, map] = imread(filename);
if isempty(img)
error('Somehow file "%s" has an empty image!', filename);
end
if ~isempty(map)
error('Somehow file "%s" is a pseudocolor JPEG image, which is not possible in standard JPEG!', filename);
end
if ndims(img) > 2
img = zeros(image_dims);
% warning('File "%s" was an RGB JPEG image (as nearly all JPEG images are), but the code expects it to one of the rare grayscale JPEG images. Substituting black image instead.', filename);
else
img = im2double(imresize(img, image_dims));
img = rgb2gray(img)
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;
% calculate the similarity of the input to each training image
input_image = imread('E:\TARGET FOLDER\0.jpg');
input_image = imresize(input_image,[64, 30]);
input_image = im2double(input_image);
input_image = rgb2gray(input_image);
input_image = size(input_image);
feature_vec = evectors' * (input_image(:) - mean_face);
i m getting error in last step of this code
plzzz plzz help to solve it out....thanx sir in advance
Walter Roberson
2017-8-10
What are you expecting the line
input_image = size(input_image);
to do for you?
Neelesh Patel
2017-8-10
Because of this error i have used that size function plzz sir solve it out because i m hunger for the result......
feature_vec = evectors' * (input_image(:) - mean_face); Error using * Inner matrix dimensions must agree.
Neelesh Patel
2017-8-10
else give me another code which gives me specific result because its a project of 'POLICE' in india so i have to design it with full effort so plz help sir....................
Walter Roberson
2017-8-10
"because its a project of 'POLICE' in india"
I am not able to assist with police or military related projects in any country. (Not even my own -- my security clearance lapsed about a month ago.)
You need to assume that anyone without a security clearance for your country, who provides you with code for facial recognition for police or military use, is a foreign or criminal antagonist with an interest in making the project fail in hidden ways.
You need to re-read the documentation on size() and you need to learn how to use the debugger to solve this problem for yourself.
Neelesh Patel
2017-8-16
0 个投票
Hello sir Plzz help me for this error:
feature_vec = evectors' * (input_image(:) - mean_face); Error using - Matrix dimensions must agree.
1 个评论
Walter Roberson
2017-8-16
You need to re-read the documentation on size() and you need to learn how to use the debugger to solve this problem for yourself.
类别
在 帮助中心 和 File Exchange 中查找有关 Image Category Classification 的更多信息
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
