README.md

PIE-torch: Poisson Image Editing in Pytorch

Fast, n-dimensional Poisson image editing.

2 implementations, including:

• using Green Function Convolution, as described in Fast and Optimal Laplacian Solver for Gradient-Domain Image Editing using Green Function Convolution
• using a Discrete Sine Transform, following OpenCV's implementation

Recommendations:

• For blending images with consistent boundaries, use blend, the Green Function Convolution implementation.
• For images with inconsistent boundaries, use blend_dst_numpy.

Main interface:

• blend: primary entrypoint, blends source image into target image at specified coordinates.
• blend_dst_numpy: entrypoint for DST-based blending (currently only available in NumPy).
• CachedPoissonBlender: calls blend but caches the Green function, so should be faster if you're repeatedly blending source patches of equal size, as you will only need to construct the Green function once.
• blend_numpy: A NumPy implementation of blend.
  • blend_wide[_numpy]: Wrappers of blend methods which allow for blending over entire image to more smoothly integrate the source region.

Why use it?

• It's faster than any available alternative (OpenCV's seamlessClone, or manual solvers using iterative methods).
• It's flexible, working on n-dimensional images, with no explicit limitations on data types (unlike seamlessClone, which only operates on 8-bit 3-channel images).
• You using it makes me feel like I'm contributing to the world.

Installation

Using pip

pip install pie-torch

Manually

Clone PIE-torch repository and install the package locally:

git clone https://github.com/matt-baugh/pytorch-poisson-image-editing.git
pip install -e ./pytorch-poisson-image-editing

You can check the installation by running the tests:

cd pytorch-poisson-image-editing/test
pytest

Usage

Example of blending normal images using mixed gradients:

from pietorch import blend

target : torch.Tensor = ... # 3 x N x M image to be blended into
source : torch.Tensor = ... # 3 x H x W image to be blended
mask : torch.Tensor = ... # H x W mask of which pixels from source to be included
corner : torch.Tensor = ... # [y, x] coordinate of location in target for source to be blended

result = blend(target, source, mask, corner, True, channels_dim=0)

Examples

A wide variety of full examples (including how to create the two below) are given in the examples notebook.

2D mixed gradient comparison with OpenCV's seamlessClone:

Target	Source

Results:

3D mixed gradient blending over spatial and temporal dimensions:

Target	Source

Result: