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resize large number of images to required size?

Ashish Sharma
Posted 7 years ago

Greetings, I am trying to implement the VGG19 neural network. I have downloaded the imagenet dataset and am testing a few classes. I have figured out that NetEncoder can be used to resize images for training but am struck with resizing the images for testing. I am using the following line of code to import the images into testData variable. 

testData = Import["C:\\Users\\cnn\\Desktop\\images\\test", "*.jpg"];

Now my problem is that the images in the folder are of various sizes and i want to resize all of them to 224 x 224 so that i can use it to test my network.

I have tried using

testData2=ImageResize[testData,{224,224}];

but it has resulted in error.

EDIT : Forgot to mention that there are two sub folders in the path. Problem has been resolved, Thank you.
POSTED BY: Ashish Sharma
8 Replies
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Ashish Sharma
Ashish Sharma
Posted 7 years ago
POSTED BY: Ashish Sharma

Use the following code:

testData = Import["C:\\Users\\cnn\\Desktop\\images\\test\\*.jpg", ImageSize -> {224, 224}]
POSTED BY: Piotr Wendykier
Ashish Sharma
Ashish Sharma
Posted 7 years ago

Thank you for your reply but I am getting the following error when I use the code you suggested:

Import::nffil: File not found during Import.

I have also tried to do the following:

testData = 
 Import["C:\\Users\\cnn\\Desktop\\images\\test\\", "*.jpg",  ImageSize -> {224, 224}]

I am getting the following error:

Import::elemstx: ImageSize->{224,224} is not a valid format or element specification. Expecting a string, list, or integer.
General::stop: Further output of Import::elemstx will be suppressed during this calculation.

can you please tell me what I am doing wrong?

Thanks

Ashish
POSTED BY: Ashish Sharma 
Import["C:\\Users\\cnn\\Desktop\\images\\test\\", "*.jpg",  ImageSize -> {224, 224}]

This is not going to work.

The code the Piotr suggested should work (if you are up-to-date with Mathematica version (I am sure this works at least on 11.1)). To be on the safe side, you could also try doing following:

files = FileNames["*.JPG" | "*.JPEG", "C:\\Users\\cnn\\Desktop\\images\\test"]
testData = Import[#, ImageSize -> {224, 224}] & /@ files;

This solution can be useful, say, when your files formats are spelled differently (i.e. JPEG vs JPG)
POSTED BY: Mikayel Egibyan
Ashish Sharma
Ashish Sharma
Posted 7 years ago
POSTED BY: Ashish Sharma

What do you want to achieve using RandomSample ? Please tell me what is the output of the following evaluation for you:

FileNames["*.JPG" | "*.JPEG", "C:\\Users\\cnn\\Desktop\\images\\test"] // Length

UPDATE

There are two sub folders in that folder namely dogs and cars

Really :) ? You should have told about that in your question. Now I don't understand how your initial code worked?

Just do following and it will work:

files = FileNames["*.JPG" | "*.JPEG", "C:\\Users\\cnn\\Desktop\\images\\test", Infinity]
testData = Import[#, ImageSize -> {224, 224}] & /@ files;
POSTED BY: Mikayel Egibyan
Ashish Sharma
Ashish Sharma
Posted 7 years ago

I just wanted to check whether the images have been imported or not using RandomSample. When I run the code you suggested it gave the following output:

Out[3]=0

I am new to MMA so I apologize for any inconvenience caused.
POSTED BY: Ashish Sharma

Please see the updated answer above.
POSTED BY: Mikayel Egibyan
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