This report summarizes the architectural evolution of the public DnCNN-Lite ECA variants, from the earliest CPU-safe versions to the later V4 and V5 scripts, and links that evolution to both denoising metrics and downstream classification behavior.
| File Version | Attention Type | Pooling | Spatial Attention | Config Style | Main Characteristics |
|---|---|---|---|---|---|
FIXED.py (V1) |
Simple ECA (fixed kernel) | Global Average Pooling | No | Hardcoded | Minimal CPU-safe ECA integration after convolution blocks. |
PATCHED.py / v2.py |
Simple ECA (fixed kernel) | Global Average Pooling | Yes (SpatialLiteAttention) |
Hardcoded | Added lightweight spatial attention to model not only which channels matter, but also where to focus spatially. |
..._v3.py (fixed-patched branch) |
Squeeze-and-Excitation (SE) | Global Average Pooling | Yes | Hardcoded | Experimental stage where ECA was temporarily replaced by an SE block with linear layers. |
FULL_PATCH_v3.py |
Advanced ECA | Global Average Pooling | Yes | Config class | Major refactor introducing DnCNNLiteECAConfig, temperature/gain controls, and mixed-precision support. |
espi_dncnn_lite_eca_FULL_PATCH_v4.py |
Advanced ECA | Global Average Pooling | Yes | Config class | Stable thesis-era version with cleaner I/O, fair ECA vs no-ECA controls, and better experiment reliability. |
espi_dncnn_lite_eca_FULL_PATCH_v5.py |
Extended ECA | Dual Pooling (avg + max) | Yes | Config class | Research-oriented extension with dual pooling, optional learnable temp/gain, multi-scale kernels, and placement presets. |
The values below summarize comparative evaluation on both synthetic validation and real ESPI pairs / averages.
| Model | Training Regime | Val PSNR (Synthetic) | Val SSIM | Val EdgeF1 | Real PSNR |
|---|---|---|---|---|---|
| V4 Baseline (NoECA) | Pseudo-noisy synthetic supervision | 27.24 dB | 0.7846 | 0.7686 | 34.58 dB |
| V4 ECA | Pseudo-noisy synthetic supervision | 27.47 dB | 0.7972 | 0.7787 | 34.50 dB |
| V5 Baseline (NoECA) | Pseudo-noisy synthetic supervision | 27.24 dB | 0.7846 | 0.7686 | 34.58 dB |
| V5 ECA (Advanced) | Pseudo-noisy synthetic supervision | 27.24 dB | 0.7852 | 0.7712 | 34.22 dB |
| V4R Baseline (NoECA) | Real pairs (23,891 images) | N/A | N/A | N/A | 23.76 dB (real validation) |
| V4R ECA | Real pairs (23,891 images) | N/A | N/A | N/A | 23.85 dB (real validation) |
- V4 ECA is clearly strongest on the reported synthetic denoising metrics, with gains of +0.23 dB PSNR and +0.0126 SSIM over the V4 baseline.
- V5 ECA, despite being architecturally more ambitious, does not consistently outperform the simpler V4 ECA configuration in the reported experiments.
- On real-aligned training pairs, adding ECA in the V4R regime provides a small but stable denoising gain over the no-ECA counterpart.
The table below summarizes how each denoising regime affected the downstream 5-class ResNet-18 classifier.
| Pre-processing Pipeline | Denoiser Training Data | ECA Enabled | Classification Accuracy (%) | Classification Macro-F1 (%) | dAcc vs Raw |
|---|---|---|---|---|---|
| No denoising (Raw) | None | No | 97.70 | 93.99 | 0.00 |
| V4 denoised | Pseudo-noisy synthetic supervision (243 images) | No | 96.39 | 89.06 | -1.31 |
| V4 denoised | Pseudo-noisy synthetic supervision (243 images) | Yes | 94.77 | 84.21 | -2.93 |
| V4R denoised (real-trained) | Real pairs (23,891 images) | No | 98.76 | 96.07 | +1.06 |
| V4R denoised (real-trained) | Real pairs (23,891 images) | Yes (V4 ECA) | 98.87 | 96.64 | +1.17 |
- Training regime dominates architecture alone. The denoisers trained on pseudo-noisy synthetic data degraded downstream classification, even when image-quality metrics looked competitive.
- Real-aligned training is the decisive factor for downstream benefit. The real-trained V4R models improved the classification pipeline over the raw baseline.
- V4R ECA is the best overall system-level result. It achieved the strongest reported downstream Accuracy and Macro-F1 in the final thesis package.