Full Waveform Inversion (FWI) is a fundamental inverse problem in geophysics to estimate subsurface properties, such as velocity, from seismic measurements. Recently, self-supervised learning methods remove the need for ground-truth velocity maps during training by leveraging a forward operator to simulate seismic data from predictions and backpropagate the gradients of reconstruction loss through it. In this work, we consider a more challenging setting without accessing such gradients. To this end, we incorporate reinforcement learning into self-supervised FWI and propose a framework named DeepWaveRL. Specifically, we reformulate FWI as a policy learning problem, where the policy network predicts velocity maps as actions, and a forward operator is used solely for simulation. A global scalar reward is computed based on data misfit for each prediction and used to weight policy gradients. Thus, learning proceeds without accessing the gradients from the forward operator. Given the indirect and coarse supervision signals, we further identify key strategies to stabilize learning and mitigate the spatial credit assignment bottleneck. Experimental results show that, despite relying entirely on a single scalar reward, DeepWaveRL achieves competitive performance compared to supervised and self-supervised baselines. These findings suggest that our framework offers a flexible and complementary learning paradigm for the FWI research community.
Figures & tables
Figure 1: Comparison between data-driven FWI methods. Top : Supervised learning methods compute loss between predicted and ground-truth velocities; Middle : Exact-gradient self-supervised learning method computes the loss between input and reconstructed seismic data and backpropagates gradients through a forward operator f ; Bottom : Our DeepWaveRL uses the forward operator solely to compute a global scalar reward based on data misfit, without accessing gradients from f .
Figure 2: Schematic illustration of the policy optimization pipeline in DeepWaveRL. For brevity, we only show the seismic data from one source.
Method
MAE ↓
RMSE ↓
SSIM ↑
InversionNet
0.0409
0.0944
0.8796
UPFWI
0.0739
0.1369
0.7420
DeepWaveRL
0.0717
0.1300
0.8303
DeepWaveRL + TTO
0.0527
0.1012
0.8601
Table 1: Quantitative results evaluated on CVA. For models with discrete predictions, we report the mean estimate.
Figure 3: Illustration of ground truth and inversion results of different methods on CVA.
Dataset
Method
MAE ↓
RMSE ↓
SSIM ↑
FFA
InversionNet
0.0098
0.0276
0.9880
UPFWI
0.0214
0.0484
0.9674
DeepWaveRL
0.0301
0.0557
0.9062
DeepWaveRL + TTO
0.0268
0.0476
0.9146
CFA
InversionNet
0.0164
0.0480
0.9721
UPFWI
0.0280
0.0641
0.9492
Table 2: Quantitative results evaluated on FFA and CFA.
Figure 4: Illustration of ground truth and inversion results of different methods on FFA (top) and CFA (bottom).
Setting
MAE ↓
RMSE ↓
SSIM ↑
Continuous Action Space
0.1443
0.2073
0.4359
Discrete Action Space
0.0527
0.1012
0.8601
Table 3: Quantitative results evaluated on CVA, with different choices of action space.
Figure 5: Illustration of ground truth and inversion results of DeepWaveRL with different choices of action space
Dataset
Fine-tuning
MAE ↓
RMSE ↓
SSIM ↑
FFA
✓
0.0268
0.0476
0.9146
0.0287
0.0520
0.9347
CFA
✓
0.0278
0.0502
0.9323
0.0358
0.0647
0.9153
Table 4: Comparison of DeepWaveRL+TTO with and without fine-tuning on the training set of FFA and CFA.
Table 10
Appendix figures & tables18 assets
Supplementary material from the paper’s appendix.
Appendix
CVA
FFA & CFA
Test-time Optimization
✓
✓
Training Steps
44,880
1,440
7,360
1,600
Initial Learning Rate
8e-4
1.6e-4
6.4e-4
6.4e-4
Learning Rate Decay
/
1,360
/
/
Batch Size
128
2048
2048
2048
Group Size
256
16
32
32
Appendix
Table 7: Training details
Method (Hardware)
CVA
FFA/CFA
InversionNet (1xH100)
51 mins
1 hr 30 mins
UPFWI (4xH100)
14 hrs 45 mins
27 hrs
DeepWaveRL (16xH100)
27 hrs
11 hrs
Appendix
Table 8: Wall-clock training time.
Method
Mean
Std
DeepWaveRL
0.3773
0.8622
UPFWI
0.3975
0.9789
InversionNet
0.3381
0.9418
Appendix
Table 9: Wall-clock inference time (single pass inference).
Dataset
Epoch
MAE ↓
RMSE ↓
SSIM ↑
CVA
720
0.0527
0.1012
0.8601
360
0.0569
0.1075
0.8524
180
0.0676
0.1172
0.8455
FFA
800
0.0268
0.0476
0.9146
400
0.0270
0.0471
0.9143
200
0.0277
0.0487
0.9134
Appendix
Table 10: Comparison of DeepWaveRL+TTO with different computation budgets.
Figure 6: Comparison of DeepWaveRL+TTO with different computation budgets on CVA (top row), FFA (middle row) and CFA(bottom row).
Figure 7: Illustration of ground truth and inversion results of SPSA and DeepWaveRL+TTO on CVA
Dataset
Method
MAE ↓
RMSE ↓
SSIM ↑
FFA
InversionNet
0.0087
0.0252
0.9893
UPFWI
0.0200
0.0429
0.9738
DeepWaveRL+TTO
0.0268
0.0476
0.9146
CFA
InversionNet
0.0155
0.0467
0.9731
UPFWI
0.0300
0.0895
0.9514
DeepWaveRL+TTO
0.0278
0.0502
0.9323
Appendix
Table 11: Comparison of different models transferred from CVA.
Dataset
Method
MAE ↓
RMSE ↓
SSIM ↑
CVA
UPFWI
0.0739
0.1369
0.7420
UPFWI+TTO
0.0666
0.1243
0.7634
DeepWaveRL+TTO
0.0527
0.1012
0.8601
FFA
UPFWI
0.0214
0.0484
0.9676
UPFWI+TTO
0.0176
0.0364
0.9778
UPFWI+TTO (CVA init.)
0.0167
0.0331
0.0.9800
Appendix
Table 12: Comparison of UPFWI with and without TTO (and with transfer learning from CVA) and DeepWaveRL+TTO.
σ2(×10−3)
PSNR
MAE ↓
RMSE ↓
SSIM ↑
0
/
0.0527
0.1012
0.8601
1
30.00
0.0593
0.1104
0.8446
5
23.01
0.0907
0.1504
0.7931
10
20.00
0.1358
0.2090
0.7418
Appendix
Table 13: Performance of DeepWaveRL+TTO tested on seismic data with different noise levels.
Figure 8: Comparison of DeepWaveRL+TTO tested on seismic data with different noise levels.
Figure 9: Illustration of ground truth and inversion results of different methods on CVA.
Figure 10: Illustration of ground truth and inversion results of different methods on FFA and CFA.
Figure 11: Comparison of DeepWaveRL+TTO with different numbers of bins on CVA.
Figure 12: Illustration of ground truth and inversion results of DeepWaveRL with and without the sign-preserving logarithm transformation
Figure 13: Comparison of DeepWaveRL with different group sizes on CVA.
Figure 14: Comparison of DeepWaveRL+TTO with and without refining the prior on the training set of FFA (top two rows) and CFA (bottom two rows).
Figure 15: Examples of failure cases where the predictions collapse to similar patterns.
Figure 16: Examples of predicted velocity maps generated by the model that has experienced unstable training.