Choosing the Best Optical Filter for Your Application

Choosing the Best Optical Filter for your Application

www.midopt.com | 1 Filters are an essential tool for increasing:

Contrast Resolution Image Quality

www.midopt.com | 2 Choose a machine vision filter that:

Enhances your imaging system

Maximizes transmission

Has superior surface quality

Is free of distortion

Can be mounted to any system

www.midopt.com | 3 BANDPASS FILTERS

• Most common filter used in machine vision

• Hybrid design with optimal blocking High Peak • Increase contrast and resolution Transmission v

Before Filter After Filter

www.midopt.com | 4 BANDPASS FILTERS

BROAD & NARROW BANDWIDTHS

BROAD • Recommended for use with LEDs to pass entire wavelength emission

Red Laser Line Broad Bandwidth Narrow Bandwidth NARROW

• Recommended for use with laser Before Filter applications that have variable angles and short field of views Narrow Bandpass Filter

• Can be used with LEDs in overwhelming ambient light conditions

• Helpful in fluorescence applications Traditional Dichroic Filter After Filter

www.midopt.com | 5 DICHROIC BANDPASS FILTERS

• Traditional interference filter

• Reflective design

• Very narrow and customizable

• Commonly used in the bio-medical industry

Broad Narrow Dichroic BP Series BN Series Bi Series

www.midopt.com | 6 Why is a hybrid design recommended over a traditional dichroic filter?

DICHROIC FILTER HYBRID FILTER

www.midopt.com | 7 What is the best filter to use over a high-temperature light source?

HYBRID FILTER

HIGH TEMPERATURE LIGHT SOURCE WITH RED FILTER DICHROIC FILTER www.midopt.com | 8 SHORTPASS FILTERS

• Useful for achieving natural color rendition

• Ideal for preventing laser damage

www.midopt.com | 9 What type of Shortpass filter is recommended to protect my camera sensor from laser damage?

Damaged sensor & image result Good sensor & imagewww.midopt.com result | 10 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

www.midopt.com | 11 Why don’t Polarizers work with polycarbonate enclosure windows?

UNPOLARIZED

PSA007 Polarizer Film PSA007 Polarizer Film & & AC380 Acrylic Filter Polycarbonate Window

POLARIZED BIREFRINGENCE www.midopt.com | 12 NEUTRAL DENSITY FILTERS

• 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

BeforeBefore Filter AfterAfter Filter www.midopt.com | 13 NEUTRAL DENSITY FILTERS

ABSORPTIVE DESIGN

• Effective from 425-675nm

• Available in optical densities ranging from 0.10 – 6.0

• Stackable to custom optical density

ND030 ND060 ND090 ND120 ND200 ND300 ND400 O.D. = 0.3 O.D. = 0.6 O.D. = 0.9 O.D. = 1.2 O.D. = 2.0 O.D. = 3.0 O.D. = 4.0

www.midopt.com | 14 NEUTRAL DENSITY FILTERS

REFLECTIVE DESIGN

• Effective from 400-2000nm

• Available in optical densities ranging from 0.3 – 1.2

• Coated on low-expansion, heat-resistant Borofloat® glass

Ni030 Ni060 Ni090 Ni120 O.D. = 0.3 O.D. = 0.6 O.D. = 0.9 O.D. = 1.2

www.midopt.com | 15 MULTIBANDPASS FILTERS

• Day/night imaging capabilities

• Achieve accurate color rendition

• Ideal for agricultural inspection / NDVI & ENDVI

• Commonly used in aerial imaging

• Can be custom sized or mounted up to 80mm

www.midopt.com | 16 Can Multibandpass filters be used on any camera?

www.midopt.com | 17 LONGPASS FILTERS

• Economical solution for isolating wavelength regions

• Can be combined with Shortpass filters

• Double-side polished with anti-reflection coating

TRADITIONAL FILTER GLASS LP340 A/R COATED GLASSwww.midopt.com | 18 ACRYLIC LONGPASS FILTERS

• Economical protection window

• Optical-grade acrylic material

• Available with anti-reflection coating

• Can be custom laser cut

• Offered for visible and near-IR imaging

www.midopt.com | 19 How does acrylic material compare to glass?

AC380 Acrylic Protective Window LP340 Glass Protective Window

www.midopt.com | 20 Is it better to mount the filter behind or in front of the lens?

Threaded Mount Filter in front of lens

25.4® C-Mount Filter behind lens www.midopt.com | 21 Key Features of Machine Vision Filters:

Stable performance at variable angles

Superior transmission and passband design

Optimal flatness and surface quality

www.midopt.com | 22 STABLE FILTERS

• Less susceptible to angle of incidence (short- shifting)

• Works well with short focal length lenses

• Superior out-of-band blocking

Red Laser Line – No Filter With StablEDGE® Filter With Traditional Filter

White Light

MidOpt BP850 Near-IR Competitor Traditional StablEDGE® Filter Interference Near-IR Filter

www.midopt.com | 23 GAUSSIAN TRANSMISSION CURVE

• Specially designed for machine vision

• Emulates the output of the most common LEDs

• Anti-reflection coatings ensure high peak transmission

• Better contrast than broad, flat-top filters

Color Image with Ambient Light Competitor Red Flat Top Filter MidOpt Red Gaussian Filter

www.midopt.com | 24 UNMATCHED OPTICAL PERFORMANCE

• Optically flat for low distortion

• Near-flawless surface quality

• Repeatable performance / lot controlled 40/20 Scratch Dig COMING • 100% quality inspection SOON

MidOpt Filter Competitor Filter

Reject Filter Good Filter

www.midopt.com | 25 AUTOMATED INSPECTION & ASSEMBLY

• Surface quality inspection

• Torque control

• Precision assembly

www.midopt.com | 26 THANK YOU

[email protected] | +1 (847) 359-3550 | www.midopt.com