A Bug That Doesn't Crash Is Worse Than One That Does — Building a QUS Python Refresher

Description and use

A silent shape mismatch in a QUS simulation caused all scatterers to be omitted, producing a zero RF array without raising an exception. Correcting the pulse length restored proper signal generation.

Problem

A silent shape mismatch in a quantitative ultrasound (QUS) simulation caused all scatterers to be omitted, producing a zero RF array without raising an exception.

Outcome

The bug was identified and fixed, restoring correct scatterer placement and RF signal generation. The repo now demonstrates a complete QUS pipeline with reproducible notebooks.

Workflow

• 1. Define short time axis for pulse generation.
• 2. Generate Gaussian envelope pulse on short axis.
• 3. Create long time axis covering full imaging depth.
• 4. Sum delayed, scaled copies of pulse onto RF array using correct bounds check.
• 5. Verify scatterer placement by counting added echoes.

Evidence

With a pulse the same length as rf, idx + len(pulse) >= len(rf) for every idx >= 0 — the condition can never be true.

Source

0 out of 200 scatterers get placed with the buggy pulse, versus 200 out of 200 with the correctly‑scoped one.

Source