Concetti Chiave
SciFlow, a novel approach that combines Self-Cleaning Iterations (SCI) and Regression Focal Loss (RFL), effectively improves the accuracy of lightweight optical flow models while preserving real-time on-device efficiency.
Sintesi
The content introduces two techniques, Self-Cleaning Iterations (SCI) and Regression Focal Loss (RFL), to enhance the capabilities of optical flow models, particularly lightweight models intended for real-time on-device applications.
SCI:
- Enables the model to "self-assess" the quality of flow estimates during the iterative refinement process.
- Compares the feature maps of the two input frames using the current estimated optical flow to derive a dense quality measure.
- Feeds this quality measure as an additional feature channel to guide the model in "self-correcting" inconsistencies in subsequent iterations.
RFL:
- Introduces a new loss function that focuses the model's learning on regions with high residual regression errors.
- Derives a confidence map based on the difference between predicted flow and ground truth.
- Applies higher weighting to regions of low confidence during training to encourage the model to improve in challenging areas.
The combination of SCI and RFL, referred to as SciFlow, is shown to be effective in mitigating error propagation, a prevalent issue in iterative refinement-based optical flow models. Experiments demonstrate that SciFlow enables substantial reduction in error metrics (EPE and Fl-all) over baseline models, with negligible additional overhead in model parameters and inference latency.
Statistiche
The baseline model (RAFT-Small) suffers from error propagation over iterations, especially near the arm and legs. (Fig. 1a)
When SCI is applied, it demonstrates a "self-cleaning" effect over iterations. (Fig. 1b)
When both SCI and RFL are applied, the "self-cleaning" effect becomes even more visible, particularly around the arm and feet. (Fig. 1c)