gotch/vision/aug/posterize.go

78 lines
1.7 KiB
Go

package aug
import (
"git.andr3h3nriqu3s.com/andr3/gotch/ts"
)
// RandomPosterize posterizes the image randomly with a given probability by reducing the
// number of bits for each color channel. If the image is torch Tensor, it should be of type torch.uint8,
// and it is expected to have [..., 1 or 3, H, W] shape, where ... means an arbitrary number of leading dimensions.
// Args:
// - bits (int): number of bits to keep for each channel (0-8)
// - p (float): probability of the image being color inverted. Default value is 0.5
// Ref. https://en.wikipedia.org/wiki/Posterization
type RandomPosterize struct {
pvalue float64
bits uint8
}
type posterizeOptions struct {
pvalue float64
bits uint8
}
type PosterizeOption func(*posterizeOptions)
func defaultPosterizeOptions() *posterizeOptions {
return &posterizeOptions{
pvalue: 0.5,
bits: 4,
}
}
func WithPosterizePvalue(p float64) PosterizeOption {
return func(o *posterizeOptions) {
o.pvalue = p
}
}
func WithPosterizeBits(bits uint8) PosterizeOption {
return func(o *posterizeOptions) {
o.bits = bits
}
}
func newRandomPosterize(opts ...PosterizeOption) *RandomPosterize {
p := defaultPosterizeOptions()
for _, o := range opts {
o(p)
}
return &RandomPosterize{
pvalue: p.pvalue,
bits: p.bits,
}
}
// NOTE. Input image must be uint8 dtype otherwise panic!
func (rp *RandomPosterize) Forward(x *ts.Tensor) *ts.Tensor {
r := randPvalue()
var out *ts.Tensor
switch {
case r < rp.pvalue:
out = posterize(x, rp.bits)
default:
out = x.MustShallowClone()
}
return out
}
func WithRandomPosterize(opts ...PosterizeOption) Option {
rp := newRandomPosterize(opts...)
return func(o *Options) {
o.randomPosterize = rp
}
}