How to Choose a Machine Vision System?
Selecting a camera, lens, and light source should begin with the defect, not the equipment catalog. Define the smallest feature, object speed, inspection distance, and surface finish.
A 0.2-millimeter scratch needs different resolution from a missing label. Monochrome cameras often reveal contrast more consistently. Color cameras help when hue carries inspection information. Global shutter models reduce distortion on moving parts.
Sensor size, pixel size, and exposure time must match the application. More megapixels do not automatically create better images.
The lens must cover the field of view without excessive distortion. A longer working distance can protect the lens from dust and vibration. Lighting controls the image more than many engineers expect.
Backlighting outlines holes and profiles.
Low-angle lighting exposes scratches and raised edges.
Diffuse lighting reduces glare on polished surfaces.
The MarketsandMarkets Machine Vision Market report projects growth from 13.0 billion dollars in 2023 to 20.9 billion dollars by 2028. This expansion reflects broader automation, but it also increases configuration mistakes.
EMVA 1288 provides practical measurements for sensitivity, signal-to-noise ratio, and dynamic range.
Tips: Test three lighting angles using real production samples. Include clean, defective, reflective, and dark parts. Keep exposure below the available cycle time. Measure images, not assumptions.
I have seen a theoretically correct lens fail because a conveyor vibrated slightly. That detail was missed during bench testing.
Recheck focus at operating temperature. A perfect setup on one part may perform poorly after dust, aging, or surface changes.