Combining multiple Principal Component Analysis (PCA) feature extractors into one. How to do it?












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I have a set of images (1000) of cats (32x32 pixels ~> flatten:1024pixels ), and want to use Principal Component Analysis to extract some features. Lets say 100 features.
Then I have basis of U_1, ... , U_1024, and i only use the first 100 vectors to extract the features. So a picture of a cat A in R^1024 is mapped to a vector x in R^100, s.th. U*x ~= A. I.e.



This works fine.



Now I get another set of 1000 images, this time dogs. I do the same procedure and get V_1, ... , V_100.



I assume that many features are quite similar, but some are different.



What I want to do now is combine the features U_1, ..., U_100, V_1, ... , V_100 to a new set of feature W_1, ... , W_100 (or maybe W_120 for example), such that I can use W on both cats and dogs. I don't want 200 features because they will be repetitive. But how to combine U's and V's in a smart way?



(Concretely my problem is that I have many sets of 500 images, and to do PCA on all images is not feasible. So I want to break it apart, and combine the PCA's.)










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  • $begingroup$
    Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
    $endgroup$
    – Moti
    Dec 17 '18 at 2:19
















0












$begingroup$


I have a set of images (1000) of cats (32x32 pixels ~> flatten:1024pixels ), and want to use Principal Component Analysis to extract some features. Lets say 100 features.
Then I have basis of U_1, ... , U_1024, and i only use the first 100 vectors to extract the features. So a picture of a cat A in R^1024 is mapped to a vector x in R^100, s.th. U*x ~= A. I.e.



This works fine.



Now I get another set of 1000 images, this time dogs. I do the same procedure and get V_1, ... , V_100.



I assume that many features are quite similar, but some are different.



What I want to do now is combine the features U_1, ..., U_100, V_1, ... , V_100 to a new set of feature W_1, ... , W_100 (or maybe W_120 for example), such that I can use W on both cats and dogs. I don't want 200 features because they will be repetitive. But how to combine U's and V's in a smart way?



(Concretely my problem is that I have many sets of 500 images, and to do PCA on all images is not feasible. So I want to break it apart, and combine the PCA's.)










share|cite|improve this question











$endgroup$












  • $begingroup$
    Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
    $endgroup$
    – Moti
    Dec 17 '18 at 2:19














0












0








0





$begingroup$


I have a set of images (1000) of cats (32x32 pixels ~> flatten:1024pixels ), and want to use Principal Component Analysis to extract some features. Lets say 100 features.
Then I have basis of U_1, ... , U_1024, and i only use the first 100 vectors to extract the features. So a picture of a cat A in R^1024 is mapped to a vector x in R^100, s.th. U*x ~= A. I.e.



This works fine.



Now I get another set of 1000 images, this time dogs. I do the same procedure and get V_1, ... , V_100.



I assume that many features are quite similar, but some are different.



What I want to do now is combine the features U_1, ..., U_100, V_1, ... , V_100 to a new set of feature W_1, ... , W_100 (or maybe W_120 for example), such that I can use W on both cats and dogs. I don't want 200 features because they will be repetitive. But how to combine U's and V's in a smart way?



(Concretely my problem is that I have many sets of 500 images, and to do PCA on all images is not feasible. So I want to break it apart, and combine the PCA's.)










share|cite|improve this question











$endgroup$




I have a set of images (1000) of cats (32x32 pixels ~> flatten:1024pixels ), and want to use Principal Component Analysis to extract some features. Lets say 100 features.
Then I have basis of U_1, ... , U_1024, and i only use the first 100 vectors to extract the features. So a picture of a cat A in R^1024 is mapped to a vector x in R^100, s.th. U*x ~= A. I.e.



This works fine.



Now I get another set of 1000 images, this time dogs. I do the same procedure and get V_1, ... , V_100.



I assume that many features are quite similar, but some are different.



What I want to do now is combine the features U_1, ..., U_100, V_1, ... , V_100 to a new set of feature W_1, ... , W_100 (or maybe W_120 for example), such that I can use W on both cats and dogs. I don't want 200 features because they will be repetitive. But how to combine U's and V's in a smart way?



(Concretely my problem is that I have many sets of 500 images, and to do PCA on all images is not feasible. So I want to break it apart, and combine the PCA's.)







statistics machine-learning






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share|cite|improve this question













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edited Dec 16 '18 at 21:52









Bernard

121k740116




121k740116










asked Dec 16 '18 at 21:35









spookyspooky

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403












  • $begingroup$
    Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
    $endgroup$
    – Moti
    Dec 17 '18 at 2:19


















  • $begingroup$
    Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
    $endgroup$
    – Moti
    Dec 17 '18 at 2:19
















$begingroup$
Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
$endgroup$
– Moti
Dec 17 '18 at 2:19




$begingroup$
Why not allow the system to select 120 (or any other preferred number of vectors) from the 2000 pictures? I am not sure that direct combination is so simple - what you attempt to do is to MIMIC Machine Learning into Human Learning - in a way you defeat the idea of machine learning that tells us that the 100 vectors from one set can be used to create a new set. Try to combine 500 of cats with 500 of dogs and see what type of vectors you get?
$endgroup$
– Moti
Dec 17 '18 at 2:19










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