Vision Lighting, Lensing & Accessories
    Machine VIsion Filters

Machine Vision Filters

Midwest Optical machine vision filters offer superior wavelength control, unmatched passband performance and high-transmission anti-reflection coating. MidOpt sets the quality standard for machine vision filters. Every filter is examined to ensure near-flawless surface quality and is 100% inspected by state-of-the-art spectrophotometer technology to ensure optimal performance and repeatability. MidOpt is also one of the only manufacturers to use controlled torque when securing filters into their mounts, eliminating distortion and guaranteeing optical flatness.

Protective Machine Vision Filters

Protection filters are designed to shield lenses and enclosures from dirt, dust, liquids, impact and harsh environments without sacrificing image quality. MidOpt offers a variety of glass and acrylic protection windows, depending on the application and environment. Glass protective filters offer superior durability, can withstand high operating temperatures and are a great solution for applications requiring exceptional surface quality. Acrylic protection windows are a cost-effective, lightweight solution for protecting the lens. MidOpt’s protection windows are offered with anti-reflection and oleophobic (anti-smudge) coating options.

• Economical solution to protect expensive lenses
• Useful for imaging in ultraviolet (UV), visible (VIS) and near-infrared (NIR) spectrums
• Available with a high-efficiency, anti-reflection coating to maximize transmission to 98% or more
• Exceptional surface quality (40/20 scratch/dig)

StablEDGE Optical Filters

MidOpt StablEDGE filters are specifically designed to be less susceptible to effects from angular shifting seen when optical filters are placed in front of short focal length (<12mm) camera lenses. This feature is becoming increasingly important as today’s trend in machine vision imaging progresses toward more compact inspection layouts, which utilize less space and force the camera and lens closer to the subject. As a result, short focal length lenses are now more widely used than ever before.

Using a traditional coated interference filter in these more compressed configurations results in contrast loss toward the edges of the image. Because of the angle imposed by the field of view of the lens, the passband shifts and allows short wavelength ambient light to overwhelm the subject. Light from LED or laser diode lighting is also cut off. In contrast, peak transmission of StablEDGE filters is not significantly altered, and effects due to short shifting are minimized.

Bandpass Filters

Bandpass Filters are specially designed for industrial imaging and are available in UV, VIS and NIR passbands. These filters achieve optimal contrast and improve system control, repeatability and stability. They block interfering wavelengths, eliminating the need for shrouds, and increase resolution by reducing chromatic aberration. Bandpass filters are used in a variety of industries, including machine vision, factory automation, security and surveillance, license plate recognition, medical and life science, agricultural inspection, aerial imaging, motion analysis, photography and cinematography.

Multi Bandpass Filters

MidOpt dual bandpass and triple bandpass filters are most commonly used for security, surveillance and intelligent traffic solutions. These filters pass visible light and a specific portion of the VIS and NIR spectrums, and are ideal for color camera applications that utilize daytime sunlight and NIR illumination at night. They achieve accurate color rendition by blocking interfering wavelengths and eliminate the need for dual sensor imaging.

Longpass Machine Vision Filters

Often referred to as a sharp-cut filter, longpass filters are specifically designed to pass a broad spectrum of longer wavelength light while blocking shorter wavelengths. This economical solution for isolating specific spectral regions has a peak transmission over 90% and features double-side polished glass for exceptional parallelism and optical flatness. StablEDGE design reduces angular dependency and minimizes short-shifting effects. These filters can be used with shortpass filters for a custom, fine-tuned bandpass filter.

Shortpass Filters

Often thought of as IR-cut filters, shortpass filters are specifically designed to pass a broad spectrum of shorter wavelength light while blocking longer VIS and NIR wavelengths. Designed to have a sharp transition between shorter wavelengths (which are passed) and longer wavelengths (which are blocked), they can be used with longpass filters for a custom, fine-tuned bandpass filter. They are available in wavelength ranges from 340 nm to 785 nm.

Neutral Density Filters

MidOpt neutral density filters serve as “sunglasses” for systems and can be used with monochrome or color cameras. Designed to reduce light intensity neutrally over a specific wavelength range without affecting image color or contrast, they are available in a variety of optical densities. These filters reduce light intensity while maintaining a wide aperture and shallow depth of field. Every 0.3 density increment equals one f-stop. They can be stacked with other neutral density filters to test various optical densities.

Polarizing Machine Vision Filters

Polarizers are designed to reduce specular glare by passing only the light polarized in the direction perpendicular to the reflected light (glare). In addition, they help improve contrast, increase color saturation and detect imperfections in transparent materials. MidOpt polarizing filters can be easily and securely mounted to lenses and light sources for maximum extinction or glare reduction. Linear, circular and wire grid polarizers are available for VIS and NIR spectrums.

Acrylic Filters

Optical-grade acrylic longpass filters are a durable, lightweight and economical solution for inspection windows and can protect a lens in environments where broken glass might pose a problem. These impact-resistant filters are half the weight of glass and have high transmission ranging from 90-98%. Acrylic filters are frequently used for lens protection and economical enclosure windows, as well as over light sources to control the wavelength emission of broad spectrum light sources.

Light Balancing Filters

Light balancing filters correct artificial lighting so colors appear more natural. These filters balance color, preventing the need for additional software processing and allowing for greater image stability and control. They achieve accurate color images when using an artificial light source and increase contrast by correcting the emission spectrum of various light sources. Different versions are used to reduce blue, red and green shading.