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tono/backend/nodes/fractal_interpolation.py

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2.9 KiB
Python

"""Fractal interpolation — fill masked regions using fractal (self-similar) synthesis."""
from __future__ import annotations
import numpy as np
from backend.node_registry import register_node
from backend.data_types import DataField
from backend.nodes.helpers import mask_to_bool
@register_node(display_name="Fractal Interpolation")
class FractalInterpolation:
@classmethod
def INPUT_TYPES(cls):
return {
"required": {
"field": ("DATA_FIELD",),
"mask": ("IMAGE",),
"iterations": ("INT", {"default": 200, "min": 10, "max": 5000, "step": 10}),
}
}
OUTPUTS = (
('DATA_FIELD', 'filled'),
)
FUNCTION = "process"
DESCRIPTION = (
"Fill masked regions using fractal interpolation. Matches the spectral "
"characteristics of the surrounding surface to produce natural-looking "
"infill that preserves texture. Better than Laplace for rough surfaces. "
)
KEYWORDS = ("inpaint", "fill", "hole", "infill")
def process(self, field: DataField, mask: np.ndarray, iterations: int) -> tuple:
data = np.asarray(field.data, dtype=np.float64).copy()
hole = mask_to_bool(mask)
if not hole.any():
return (field.replace(data=data),)
# Step 1: Estimate power spectrum from valid (unmasked) data
valid_data = data.copy()
valid_mean = data[~hole].mean() if (~hole).any() else 0.0
valid_data[hole] = valid_mean
fft_valid = np.fft.fft2(valid_data)
power = np.abs(fft_valid) ** 2
# Step 2: Generate fractal noise matching the power spectrum
rng = np.random.default_rng(42)
phases = rng.uniform(0, 2 * np.pi, data.shape)
noise_fft = np.sqrt(power) * np.exp(1j * phases)
noise = np.real(np.fft.ifft2(noise_fft))
# Normalize noise to match local statistics around masked region
if (~hole).any():
noise = (noise - noise[~hole].mean()) / max(noise[~hole].std(), 1e-30) * \
data[~hole].std() + data[~hole].mean()
# Step 3: Initialize masked pixels with fractal noise, then blend
# with Laplace relaxation for smooth boundaries
data[hole] = noise[hole]
# Relax boundaries to ensure continuity
padded = np.pad(data, 1, mode='edge')
hole_padded = np.pad(hole, 1, mode='constant', constant_values=False)
for _ in range(iterations):
avg = (padded[:-2, 1:-1] + padded[2:, 1:-1] +
padded[1:-1, :-2] + padded[1:-1, 2:]) / 4.0
# Blend: 90% fractal noise + 10% relaxation to smooth boundaries
blend = 0.1
new_vals = (1.0 - blend) * padded[1:-1, 1:-1][hole] + blend * avg[hole]
padded[1:-1, 1:-1][hole] = new_vals
data = padded[1:-1, 1:-1].copy()
return (field.replace(data=data),)