public static (NDArray, (int, int, int, int)) RandomExpand(NDArray src, float max_ratio = 4, float fill = 0, bool keep_ratio = true)
{
ndarray dst;
float ratio_y;
if (max_ratio <= 1)
{
return(src, (0, 0, src.Shape[1], src.Shape[0]));
}
var(h, w, c) = src.Shape;
var ratio_x = FloatRnd.Uniform(1, max_ratio);
if (keep_ratio)
{
ratio_y = ratio_x;
}
else
{
ratio_y = FloatRnd.Uniform(1, max_ratio);
}
var oh = Convert.ToInt32(h * ratio_y);
var ow = Convert.ToInt32(w * ratio_x);
var off_y = IntRnd.Uniform(0, oh - h);
var off_x = IntRnd.Uniform(0, ow - w);
// make canvas
dst = nd.Full(fill, shape: new Shape(oh, ow, c), dtype: src.DataType).AsNumpy();
dst[$"{off_y}:{(off_y + h)}", $"{off_x}:{(off_x + w)}", ":"] = src;
return(dst, (off_x, off_y, ow, oh));
}
public override NDArray Call(NDArray src)
{
var alpha = 1f + FloatRnd.Uniform(-Saturation, Saturation);
var gray = src * coef;
gray = nd.Sum(gray, 2, true);
gray *= 1 - alpha;
src *= gray;
src += gray;
return(src);
}
public override NDArray Call(NDArray src)
{
float alpha = FloatRnd.Uniform(-Hue, Hue);
var u = (float)Math.Cos(alpha * Math.PI);
var w = (float)Math.Sin(alpha * Math.PI);
var bt = new NDArray(new[] { 1, 0, 0, 0, u, -w, 0, w, u }).Reshape(3, 3);
var t = nd.Dot(nd.Dot(ITyiq, bt), Tyiq).Transpose();
src = nd.Dot(src, t);
return(src);
}
public static (NDArray, (bool, bool)) RandomFlip(NDArray src, float px = 0, float py = 0, bool copy = true)
{
var flip_y = FloatRnd.Uniform(0, 1 - py);
var flip_x = FloatRnd.Uniform(0, 1 - px);
if (flip_y > 0.5f)
{
src = nd.Flip(src, axis: 0);
}
if (flip_x > 0.5f)
{
src = nd.Flip(src, axis: 1);
}
if (copy)
{
src = src.Copy();
}
return(src, (flip_x > 0.5f, flip_y > 0.5f));
}
