Data augmentation is important to train models with good generalization ability, especially when the size of your dataset is limited. FastAI.jl gives you high-level helpers to use data augmentation in vision learning tasks, but also allows directly using DataAugmentation.jl , the underlying data augmentation library.
By default, the only augmentation that will be used in computer vision tasks is a random crop, meaning that after images, keypoints and masks are resized to a similar size a random portion will be cropped during training. We can demonstrate this on the image classification task.
using
FastAI
,
FastVision
,
FastMakie
import
CairoMakie
;
CairoMakie
.
activate!
(
type
=
"
png
"
)
data
,
blocks
=
load
(
datarecipes
(
)
[
"
imagenette2-160
"
]
)
task
=
BlockTask
(
blocks
,
(
ProjectiveTransforms
(
(
128
,
128
)
)
,
ImagePreprocessing
(
)
,
OneHot
(
)
)
)
xs
,
ys
=
FastAI
.
makebatch
(
task
,
data
,
fill
(
4
,
3
)
)
showbatch
(
task
,
(
xs
,
ys
)
)
LoadError("string", 14, ArgumentError("The attribute `textsize` has been renamed to `fontsize` in Makie v0.19. Please change all occurrences of `textsize` to `fontsize` or revert back to an earlier version."))
Most learning tasks let you pass additional augmentations as keyword arguments. For example,
ImageClassification takes the
aug_projection and
aug_image arguments. FastAI.jl provides the
augs_projection helper to quickly construct a set of projective data augmentations.
task2
=
BlockTask
(
blocks
,
(
ProjectiveTransforms
(
(
128
,
128
)
,
augmentations
=
augs_projection
(
)
)
,
ImagePreprocessing
(
)
,
OneHot
(
)
)
)
xs2
,
ys2
=
FastAI
.
makebatch
(
task2
,
data
,
fill
(
4
,
3
)
)
showbatch
(
task2
,
(
xs2
,
ys2
)
)
LoadError("string", 10, ArgumentError("The attribute `textsize` has been renamed to `fontsize` in Makie v0.19. Please change all occurrences of `textsize` to `fontsize` or revert back to an earlier version."))
Likewise, there is an
augs_lighting helper that adds contrast and brightness augmentation:
task3
=
BlockTask
(
blocks
,
(
ProjectiveTransforms
(
(
128
,
128
)
,
augmentations
=
augs_projection
(
)
)
,
ImagePreprocessing
(
augmentations
=
augs_lighting
(
)
)
,
OneHot
(
)
)
)
xs3
,
ys3
=
FastAI
.
makebatch
(
task3
,
data
,
fill
(
4
,
3
)
)
showbatch
(
task3
,
(
xs3
,
ys3
)
)
LoadError("string", 10, ArgumentError("The attribute `textsize` has been renamed to `fontsize` in Makie v0.19. Please change all occurrences of `textsize` to `fontsize` or revert back to an earlier version."))