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Poisson denoising using Poisson2Sparse#
This code shows how to restore a single image corrupted by Poisson noise using Poisson2Sparse, without requiring external training or knowledge of the noise level.
This method is based on the paper βPoisson2Sparseβ Ta et al.[1] and restores an image by learning a sparse non-linear dictionary parametrized by a neural network using a combination of Neighbor2Neighbor Huang et al.[2], of the negative log Poisson likelihood, of the \(\ell^1\) pixel distance and of a sparsity-inducing \(\ell^1\) regularization function on the weights.
import deepinv as dinv
import torch
Load a Poisson corrupted image#
This example uses an image from the microscopy dataset FMD Zhang et al.[3].
# Seed the RNGs for reproducibility
torch.manual_seed(0)
torch.cuda.manual_seed(0)
device = dinv.utils.get_freer_gpu() if torch.cuda.is_available() else "cpu"
physics = dinv.physics.Denoising(dinv.physics.PoissonNoise(gain=0.01, normalize=True))
x = dinv.utils.demo.load_example(
"FMD_TwoPhoton_MICE_R_gt_12_avg50.png", img_size=(256, 256)
).to(device)
x = x[:, 0:1, :64, :64]
x = x.clamp(0, 1)
y = physics(x)
Selected GPU 0 with 3730.25 MiB free memory
Define the Poisson2Sparse model
backbone = dinv.models.ConvLista(
in_channels=1,
out_channels=1,
kernel_size=3,
num_filters=512,
num_iter=10,
stride=2,
threshold=0.01,
)
model = dinv.models.Poisson2Sparse(
backbone=backbone,
lr=1e-4,
num_iter=200,
weight_n2n=2.0,
weight_l1_regularization=1e-5,
verbose=True,
).to(device)
Run the model#
Note that we do not pass in the physics model as Poisson2Sparse assumes a Poisson noise model internally and does not depend on the noise level.
x_hat = model(y)
# Compute and display PSNR values
learning_free_psnr = dinv.metric.PSNR()(y, x).item()
model_psnr = dinv.metric.PSNR()(x_hat, x).item()
print(f"Measurement PSNR: {learning_free_psnr:.1f} dB")
print(f"Poisson2Sparse PSNR: {model_psnr:.1f} dB")
# Plot results
dinv.utils.plot(
[y, x_hat, x],
titles=["Measurement", "Poisson2Sparse", "Ground truth"],
subtitles=[f"{learning_free_psnr:.1f} dB", f"{model_psnr:.1f} dB", ""],
)

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29%|βββ | 58/200 [00:01<00:04, 31.18it/s]
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33%|ββββ | 66/200 [00:02<00:04, 31.53it/s]
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41%|ββββ | 82/200 [00:02<00:03, 31.70it/s]
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51%|βββββ | 102/200 [00:03<00:03, 32.00it/s]
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69%|βββββββ | 138/200 [00:04<00:01, 31.49it/s]
71%|βββββββ | 142/200 [00:04<00:01, 31.15it/s]
73%|ββββββββ | 146/200 [00:04<00:01, 30.77it/s]
75%|ββββββββ | 150/200 [00:04<00:01, 30.96it/s]
77%|ββββββββ | 154/200 [00:04<00:01, 31.02it/s]
79%|ββββββββ | 158/200 [00:05<00:01, 31.42it/s]
81%|ββββββββ | 162/200 [00:05<00:01, 31.42it/s]
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87%|βββββββββ | 174/200 [00:05<00:00, 31.67it/s]
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99%|ββββββββββ| 198/200 [00:06<00:00, 31.45it/s]
100%|ββββββββββ| 200/200 [00:06<00:00, 31.33it/s]
Measurement PSNR: 27.5 dB
Poisson2Sparse PSNR: 30.3 dB
- References:
Total running time of the script: (0 minutes 7.205 seconds)