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from fastai.vision import *   # Quick access to computer vision functionality

Vision example¶

Images can be in labeled folders, or a single folder with a CSV.

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path = untar_data(URLs.MNIST_SAMPLE)
path

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PosixPath('/home/ubuntu/.fastai/data/mnist_sample')

Create a DataBunch, optionally with transforms:

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data = ImageDataBunch.from_folder(path, ds_tfms=(rand_pad(2, 28), []), bs=64)
data.normalize(imagenet_stats)
img,label = data.train_ds[0]
img

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Create and fit a Learner:

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learn = cnn_learner(data, models.resnet18, metrics=accuracy)
learn.fit_one_cycle(1, 0.01)

epoch	train_loss	valid_loss	accuracy	time
0	0.046350	0.008395	0.997547	00:06

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accuracy(*learn.get_preds())

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tensor(0.9975)

Same as above, using CSV instead of folder name for labels

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data = ImageDataBunch.from_csv(path, ds_tfms=(rand_pad(2, 28), []), bs=64)
data.normalize(imagenet_stats)
img,label = data.train_ds[0]
img

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learn = cnn_learner(data, models.resnet18, metrics=accuracy)
learn.fit_one_cycle(1, 0.01)

epoch	train_loss	valid_loss	accuracy	time
0	0.055503	0.007956	0.996881	00:05