While lens quality, illumination level and aperture size are all important considerations in designing a machine vision system, colored filters can be instrumental in achieving the highest contrast images possible. Though seemingly insubstantial, colored filters are essential for achieving excellent image contrast and improving the overall performance of machine vision systems. They offer impressive individual benefits, only minimally impact other system design considerations in the event of replacement or upgrade, and are available at a reasonable cost. Regardless of the spectral characteristics of the objects a machine vision system is used to evaluate, there is a colored filter, or combination of colored filters, perfect for the job. United Lens Company (ULC) has been manufacturing high quality colored filters for years.
Why Colored Filters?
There are four primary types of colored filters: longpass filters, shortpass filters, bandpass filters and notch filters. Longpass filters block short wavelengths of light (purples and blues) while allowing long wavelengths (yellows and reds) to pass; shortpass filters are the opposite, blocking long wavelengths and passing short ones. Bandpass filters block all wavelengths except for central wavelengths (greens); notch filters pass a narrow central band of wavelengths and block the others.
Colored filters are angle-independent, meaning their optical transmission will not shift when used with different lenses or at angles. They are most effective in applications where the imaged objects have spectral requirements on the broader side.
ULC offers an expansive range of round and square colored filters, suitable for use in several machine imaging systems. All of our colored filters are manufactured to our strict quality standards with SCHOTT optical filter glass.
Round colored filters are available at 25.40mm in diameter and 3mm in thickness, with a flatness of less than 2 waves at 632.8 nanometers, and a wedge of less than 3 arcminutes. Square colored filters are available at 50.80mm in length and width, 3mm thick, with a flatness of less than 4 waves at 632.8 nanometers.
Colored Filters from ULC
Visit ULC’s online catalog—redesigned using fully integrated software to make our customers’ shopping experience easier than ever—to learn more about our colored filters, round colored filters and square colored filters alike.