Consistent Video Depth

Consistent video depth is the requirement that depth predictions remain temporally coherent across consecutive frames while respecting camera motion and scene geometry - without this consistency, frame-wise depth outputs flicker and degrade downstream performance.

What Is Consistent Video Depth?

• Definition: Depth sequence where corresponding scene points maintain stable depth relationships over time.
• Main Problem: Independent per-frame monocular depth often jitters despite visually stable content.
• Consistency Signal: Warp-based temporal alignment and geometric reprojection constraints.
• Output Goal: Smooth, physically plausible depth trajectories.

Why Consistent Depth Matters

• Visual Quality: Eliminates depth flicker in AR and rendering applications.
• SLAM Compatibility: Stable depth improves pose and map estimation.
• 3D Reconstruction: Coherent depth reduces temporal artifacts in fused geometry.
• Planning Reliability: Consistent obstacle depth supports safer control decisions.
• Model Trust: Temporal stability improves confidence in depth-driven systems.

Consistency Enforcement Methods

Temporal Warping Loss:
- Compare current depth with motion-warped previous depth.
- Penalize inconsistency outside occluded regions.

Sequence Refinement Networks:
- Recurrent or transformer modules smooth depth trajectories.
- Preserve sharp boundaries with edge-aware constraints.

Test-Time Adaptation:
- Online fine-tuning can reduce depth jitter in specific sequences.
- Useful for long-run deployment settings.

How It Works

Step 1:
- Predict depth per frame and estimate inter-frame motion correspondences.

Step 2:
- Apply temporal consistency objectives and refinement to stabilize depth across the sequence.

Consistent video depth is the temporal quality criterion that turns plausible single-frame depth into reliable sequence-level 3D perception - it is essential for production systems that consume depth over time.