Wavelength Control in Machine Vision: Why Filters Matter

In machine vision, optical filters aren’t just add-ons, they’re essential tools for image accuracy. By carefully controlling which wavelengths pass through (and which don't), filters help maximize contrast, enhance color accuracy, highlight critical details and block ambient light that can compromise results.

Why Standard Filters Struggle

One of the biggest drawbacks of using traditional interference filters is “short-shifting.” When used with short focal length lenses (typically under 12mm) or in wide FOV (field-of-view) setups, the filter’s passband shifts at the edges. Short-shifting results in reduced contrast and unwanted shorter wavelengths – often blue light – bleeding into the image. That shift can mean the difference between crisp, reliable data and blurred, unusable output.

StablEDGE® Technology: Designed for Stability

This is where MidOpt® StablEDGE® filters make the difference. By integrating absorptive filter glass at the leading edge of the passband, StablEDGE® ensures stable wavelength performance even at extreme viewing angles of over 100°, preventing shifting and keeping images sharp from edge to edge.

Unlike many filters with flat-top transmission profiles, MidOpt® bandpass filters are designed to emulate the Gaussian, bell-shaped spectral output of the most common LEDs. This alignment ensures the filter captures the most effective part of the illumination spectrum while reducing noise from the tail ends. The result is higher contrast and consistently cleaner imaging.

Additional Advantages of MidOpt® Filters

• High-Transmission AR (Anti-Reflection) Coatings – Reduce reflection losses to less than 1%, increasing light throughput and minimizing ghosting.
• Quality & Repeatability – Double-side polished for near-flawless surfaces (40/20 scratch-dig or better), each filter undergoes strict spectral testing. Torque-controlled mounting preserves flatness and eliminates distortion, ensuring reliable results every time.

For compact, wide-angle or precision-driven machine vision systems, standard filters often fall short. MidOpt® StablEDGE® technology solves these challenges, providing stable, angle-independent wavelength control that keeps images clear, consistent and dependable. In today’s demanding applications, that level of reliability isn’t just helpful – it’s essential.