Motion Blur.

The math here is the canonical kinematic-blur reading: a part moving at constant velocity v perpendicular to the optical axis translates by Δx = v · t over an exposure window of length t. That object-space translation maps to blur_px = Δx / p pixels of blur on the sensor when projected through the lens-and-sensor magnification (object-space pixel size p is sensor pitch divided by magnification — the upstream output of the Object-Space Pixel Size calc). At default 500 mm/s + 100 μs + 50 μm pixel size the calc lands blur_obj = 50 μm and blur_px = 1.0 — the canonical pixel-budget register where motion fills exactly one sensor pixel during exposure, the standard MV-screening sweet spot. The relationship is bilinear in speed × time and inverse in pixel size: doubling speed at constant exposure doubles blur; doubling exposure at constant speed doubles blur; halving the object-space pixel size (e.g. by doubling magnification) doubles the pixel-blur reading at constant object-space blur.

The exposure-vs-blur tradeoff is the central knob in motion-driven MV setup: longer exposures admit more light (better SNR; less aperture forced open; less strobe pulse-energy required) but more motion blur; shorter exposures preserve sharpness but demand more light from the illumination system. Practitioners typically pick a target pixel-blur register (sub-pixel for metrology; pixel-budget for screening; blur-tolerant for reading-only inspection) and back-solve the exposure ceiling from that target — given speed v + pixel size p + target blur_px_max, the maximum exposure is t_max = (blur_px_max · p) / v (the inverse reading; run the Max Exposure per Line calc for that direction). At default 500 mm/s + 50 μm pitch + 1-px target, t_max ≈ 100 μs — exactly what the default exposure delivers. At higher line speeds (1000–2000 mm/s typical for high-throughput inspection) the same one-pixel budget collapses to 25–50 μs, which usually forces a strobe-illumination decision (the Strobe Duty Cycle calc determines the maximum strobe pulse energy at that pulse width). Higher-still speeds (3000+ mm/s) often exceed area-scan motion-blur tolerance entirely and migrate the inspection to line-scan geometry, where the relationship becomes line-rate-keyed instead — see the Along-Scan Pixel Size and Line Rate for Square Pixels calcs.

How small a motion-blur is right depends on what the inspection task needs to resolve at the part frame — but the pixel-blur ratio also tells you immediately what regime the configuration sits in. The pixel-blur register below the diagram reads off the ratio directly: sub-pixel (blur_px < 0.5) reads as effectively static (the motion contributes less than half a pixel of smear; metrology-grade and most screening tasks land here); pixel-budget (0.5–1.5) is the standard MV-screening sweet spot where motion fills roughly one pixel (default lands here at 500 mm/s + 100 μs + 50 μm); blur-tolerant (1.5–3) is multi-pixel smear that's workable for shape-recognition or barcode-reading tasks where sub-pixel localization isn't required; blur-dominant (3–6) is where motion blur dominates the image quality and the practitioner must choose between strobing, slowing down the line, or accepting reduced inspection fidelity; streak (≥ 6) is extreme territory typical of fast-line under-strobed inspection or insufficient illumination forcing long exposures. The pixel-blur register is the operational dial — the practitioner walks it down by shortening exposure (more illumination required), reducing speed (throughput cost), or coarsening object-space pixel size (lower magnification or larger sensor pitch — both with their own resolution tradeoffs).