Adaptive ΔE00 feedback control: engineering GPU-resident perceptual locks for Shadow’s MiniMax Direct multimodal rendering pipeline

Description and use

A GPU‑resident ΔE00 feedback loop keeps real‑time rendering color consistent with a master reference, eliminating perceptual drift.

Problem

Perceptual drift in real‑time rendering causes skin tones and logos to shift color over long playback, degrading visual fidelity.

Outcome

The system eliminates perceptual drift, keeping output color consistent with the master reference while running entirely on the GPU with no per‑frame readbacks.

Workflow

• 1. Sample color tiles from master reference and rendered output in a compute shader using ΔE00.
• 2. Aggregate per‑tile errors and run a PID‑style adaptive controller in a second compute shader.
• 3. Write updated transform coefficients to a uniform buffer.
• 4. Consume updated coefficients in the next frame before tone mapping and gamut compression.
• 5. Host‑side TypeScript orchestrator boots the pipeline, binds textures, dispatches shaders, and collects coarse telemetry every ~250 ms.

Evidence

We precompute the L*a*b* conversion in a lookup texture and only run the rotation term in the inner loop.

Source

Everything stays in VRAM. We have a hard rule: no readbacks per frame.

Source