Choosing the Best Optical Filter for Your Application. Georgy Das Midwest Optical Systems, Inc.

Transcription

1 Choosing the Best Optical Filter for Your Application Georgy Das Midwest Optical Systems, Inc.

2 Filters are a Necessity, Not an Accessory.

3 Key Terms Transmission (%) OUT-OF-BAND PASSBAND TRANSMISSION BP UV VISIBLE NIR SWIR

4 Filters are Essential for Increasing Contrast Resolution Repeatability

5 Increase Contrast

6 Increase Contrast MidOpt BP635 Red Bandpass Filter MidOpt BP470 Blue Bandpass Filter Original Color Image No Filter

7 White Light Increase Resolution Before Bandpass Filter After Bandpass Filter NIR NIR VIS VIS UV UV Chromatic Aberration is a type of distortion in which the lens does not focus all colors to the same convergence point

8 Repeatability Filters are the most cost effective way to improve repeatability and stability in any machine vision system. Achieve consistent results with Machine Vision Filters

9 Types of Filters Shortpass Longpass Acrylic Polarizers Neutral Density Multi-Bandpass

10 Shortpass Pass short wavelengths, while blocking long wavelengths Useful for achieving natural color rendition BEFORE FILTER AFTER FILTER

11 Shortpass Ideal for preventing laser damage Reflective vs. Absorptive

12 Longpass Economical solution for isolating wavelength regions Can be combined with Shortpass Filters

13 Longpass Recommended when imaging in the NIR with a CCD/CMOS sensor

14 Acrylic Economical protection window Optical-grade acrylic material Available with anti-reflection coating Can be custom laser cut Offered for visible and near-ir imaging

15 Acrylic UNPOLARIZED PSA007 Polarizer Film & AC380 Acrylic Filter PSA007 Polarizer Film & Window Polycarbonate POLARIZED BIREFRINGENCE

16 Polarizers Use a Polarizing Filter and Bandpass Filter to improve image quality. Glare from LED and ambient light Significant glare remains Minimal glare from ambient light remains Further reduces glare and improves contrast No Filter Polarizing Filter Polarizing Filter Polarizing Film Polarizing Filter Polarizing Film Red Bandpass Filter

17 Polarizers FILM & SHEET MATERIAL Can be custom cut to any shape or size Available in high-temperature-resistant laminate or glass Offered with self-adhesive backing Most effective when used with polarizing filter

18 Polarizers Reduce reflections and specular glare Designed for visible and near-infrared spectrums Offered in contrast ratios averaging 10,000:1 Available in a variety of options: Linear Circular Wire Grid

19 Neutral Density Sunglasses for your system Reduce light intensity Create a shallow depth of field Increase exposure and slow shutter speed Offered in absorptive and reflective options Before Filter After Filter

20 Neutral Density Stack Neutral Density Filters to create a custom optical density.

21 Multi-Bandpass Day/night imaging capabilities Achieve accurate color rendition Eliminate the need for dual sensor imaging Most commonly used in ITS and surveillance applications

22 UV Fluorescence Imaging Without filtering, the excitation light source interferes with weaker emitted fluorescence Original Color Image No Filter With MidOpt BP470 Blue Bandpass Filter

23 Key Features of Machine Vision Filters Wavelength control Passband performance High-transmission anti-reflection coating Optimal performance and repeatability Convenient mounting solutions

24 Wavelength Control AOI - The angle of incidence that light passes through a surface Machine vision filters have optimal performance at variable angles Designed to be used with short and long focal length lenses Superior out-of-band blocking

25 White Light Wavelength Control

26 Passband Performance Gaussian bell shape design is ideal for machine vision Emulates the output of the most common LEDs Better contrast than broad, flat-top filters Color Image with Ambient Light Red Flat Top Filter (w/ ambient light) Red Gaussian Filter (w/ ambient light)

27 Anti-Reflection Coating

28 Anti-Reflection Coating Filter with No Coating Filter with MgF2 Single-Layer Coating Filter with BBAR Multi-Layer Coating

29 Unmatched Optical Performance Optically flat for low distortion Near-flawless surface quality Repeatable performance 100% quality inspection PV: wave PV: wave with distortion without distortion with scratches/digs without scratches/digs

30 Next-Gen Applications SWIR - Short-Wave Infrared Imaging 3-D metrology NDVI (Normalized Difference Vegetation Index)

31 Next-Gen Applications SWIR In-gas camera sensor spectral response (900nm-2000nm)

32 Next-Gen Applications SWIR - Short-Wave Infrared Imaging Moisture detection nm LIDAR for autonomous vehicles nm+ Visible light SWIR 1450nm moisture detection

33 Next-Gen Applications 3-D metrology Quality control is becoming increasingly automated 3-D scanning provides the data to inspect forms, tools, castings and assemblies such as car bodies

34 Next-Gen Applications NDVI (Normalized Difference Vegetation Index) Crop health - plants reflect light at different levels based on their health Combination of software, aerial equipment and wavelength filtering

35 Georgy Das Technical Training Manager Midwest Optical Systems, Inc. Palatine, IL, USA