Using Filters in Machine Vision Systems

In machine vision system design, enhancing image contrast is a primary consideration. While proper lighting, aperture size, and lens selection can improve contrast, integrating the right optical filter often achieves this more cost-effectively—with minimal impact on other system components.

Types of Machine Vision Filters

Machine vision filters fall into two main categories:

1. Absorptive Filters

These filters use heavy metal-doped glass to selectively absorb specific light wavelengths. They remain widely used due to two key advantages: lower cost and angle insensitivity (performance stays consistent across varying incident angles).

2. Interference Filters

These filters rely on thin-film interference to control light transmission/reflection. Compared to absorptive types, high-quality interference filters offer superior performance: higher transmittance, deeper cut-off (for unwanted wavelengths), and steeper spectral edges—critical for precise image contrast.

OPTOStokes’ Machine Vision Filters: Engineered for Excellence

OPTOStokes’ vision filters are interference-type, manufactured using advanced coating techniques. They outperform absorptive filters with:

• High transmittance: Maximizes signal from target wavelengths, enhancing image clarity.
• Deep cut-off: Effectively blocks stray light, reducing noise in critical applications.
• Steep spectral edges: Sharply separates desired and unwanted wavelengths, improving contrast in fine detail detection (e.g., barcode reading, defect inspection).

Wide Field of View (FOV) Performance

Modern machine vision systems increasingly use short-focal-length lenses to boost integration—resulting in larger FOVs. Conventional interference filters typically perform well only within a narrow incident angle range (0–5°), with significant spectral distortion or blue-shifting beyond 10° FOV.

OPTOStokes addresses this through precision film design, optimization, and strict thickness control. Our filters maintain stable spectral performance even at a 30° FOV—ideal for wide-angle systems in automation, robotics, and high-speed inspection lines.

Why Choose OPTOStokes for Your Machine Vision Needs?

Whether you need off-the-shelf filters for standard systems or custom designs tailored to your specific wavelength, FOV, or environmental requirements, OPTOStokes delivers. Our filters meet international quality standards, with reliable lead times to keep your production on track.

Struggling with contrast issues in wide-FOV systems? Need a filter that performs consistently across large angles? Contact our team at sales@optofilters.com or leave a message on our website. We’ll help you select the perfect filter to optimize your machine vision system.