Test Targets

For assessing the resolution capabilities of, for example, optics and cameras, we offer test targets on which test structures with different resolutions are present. Two versions are currently available as standard.

Siemens star resolution test pattern

The Siemens star was developed by Siemens AG (then Siemens & Halske AG) in the 1930s. With this test pattern, the quality of optical imaging systems can be checked.

• 1–25 LP/mm
• 20 × 20 cm
• Barite paper 255 g: Article number: 06.28.0001
• Transparent foil: Article number: 06.28.0003

To show how the Siemens star works, we have calculated images with HDTV resolution (i.e. 1920 × 1080 pixels, reduced to 1080 × 1080) and various levels of blurring.

With 1080 pixels and an image height of 20 cm, that is 137.16 ppi or 0.185 mm/pix. Nyquist is thus 2.7 LP/mm for monochrome and 1.35 LP/mm for color (Bayer pattern).

At higher spatial frequencies of the template, moirés occur as a result of oversampling, which can lead to problems with the evaluation, especially in machine vision applications. For metrological purposes, it is therefore often helpful to use a reasonable amount of well-defined blur.

In order to make the differences between the various blurs clear, we show composite images here (one monochrome, one color):

• top left: without MTF limitation
• right-top: 3.0 LP/mm @ 50 % MTF
• right-bottom: 2.0 LP/mm @ 50 % MTF
• left-bottom: 1.0 LP/mm @ 50 % MTF

It is important that the targets are only viewed on the monitor in 1:1 mode (click for original view), as each scaling produces additional artifacts! This type of calculation has already been well tested at Eureca and has been verified several times by practical recordings with real lenses under real conditions.

USAF-1951 resolution test pattern

This test chart was designed by the United States Air Force (USAF) in 1951 to check the resolution of aerial cameras and other optical instruments.

• 0.0625–28.5 LP/mm
• 20 × 20 cm
• Barite paper 255 g: Article number: 06.28.0002
• Transparent foil: Article number: 06.28.0004

The test targets are manufactured internally at Eureca. Customized versions on paper or film, with test structures individually tailored to the respective measurement task, are also possible on request.

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