Optimizing AI Inference with NPU

What Is an NPU

An NPU (Neural Processing Unit) is a hardware accelerator designed specifically for AI inference. The RV1126B integrates a 2.0 TOPS NPU.

Three Optimization Steps

1. Quantization (INT8)

Quantizing FP32 models to INT8 improves inference speed by 3–4x.

2. Model Architecture Optimization

Adjust layer configurations to suit the NPU. Certain operations require CPU fallback.

3. Accelerating Pre/Post-processing

Leverage OpenCV’s NEON optimizations and GStreamer’s hardware-accelerated color conversion.

Measured Performance

Inference time with IMX415 input and YOLOv5s (INT8 quantization):

• CPU only: approx. 180ms
• NPU: approx. 25ms (approximately 7x speedup)

Summary

With proper quantization and pipeline optimization, practical AI inference performance is achievable.