Grid Distortion Test Targets

Click to Enlarge
An R2L2S3P3 Target Post Mounted via an FFM1 Filter Mount and a B3C Cube Base for Use in a Custom Imaging System

Click for Details
A Close Up of the Dot Pattern on the R2L2S3P4 Target

• One Grid Array on a 1.5" x 1.5" (38.1 mm x 38.1 mm) Soda Lime Glass Substrate
• 125 µm, 250 µm, 500 µm, or 1000 µm Grid Spacings
• Ø62.5 µm, Ø125 µm, Ø250 µm, or Ø500 µm Dots
• Ideal for Machine Vision Applications of Stage Calibration and Distortion Detection

These distortion grid arrays each feature a single grid of dots fabricated from the deposition of vacuum-sputtered, low-reflectivity chrome on a soda lime glass substrate. The available grid spacings, which are measured from the center of any dot to the center of any adjacent dot, range from 125 µm to 1000 µm, and the dot diameters range from 62.5 µm to 500 µm.

Grid arrays are used to determine the distortion of an imaging system. Ideally, the horizontal and vertical rows of dots should be perpendicular to each other. A distorted image will show the array as bowed; this image can then be used to correct for distortion.

Click to Enlarge
Close Up of the Four Grid Patterns on the R1L3S3P Target

• Four Grid Arrays on a 3" x 1" (76.2 mm x 25.4 mm) Soda Lime Glass Slide
• 10 µm, 50 µm, 100 µm, and 500 µm Grid Spacings
• Ideal for Microscopy Applications of Stage Calibration and Distortion Detection
• Same Outer Dimensions as a Standard Microscope Slide
• High Contrast Positive Reflective Target Available

These grid distortion targets feature four arrays of horizontal and vertical lines spaced 10 µm, 50 µm, 100 µm, and 500 µm apart. This pattern is fabricated from the deposition of low-reflectivity, vacuum-sputtered chrome on a 3" x 1" x 0.06" (76.2 mm x 25.4 mm x 1.5 mm) soda lime glass substrate. The dimensions of the glass substrate are the same as a standard microscope slide.

Thorlabs offers two targets composed of a low-reflectivity chrome pattern etched on soda lime glass. The R1L3S3P positive target has the clear soda lime substrate background for for front-lit and general applications, while the R1L3S3PR positive reflective target has a chrome background for high contrast in reflective applications. See the Graphs tab for details.

Grid arrays are used to determine the distortion of an imaging system. Ideally, the horizontal and vertical lines of the grid should be perpendicular to each other. A distorted image will show the lines as bowed; this image can then be used to correct for distortion.

Click to Enlarge
Close Up of R1L3S14N Ronchi Ruling Pattern

• 3" x 1" (76.2 mm x 25.4 mm) Square Wave Ronchi Ruling Target
• Patterns with 10 lp/mm Up to 350 lp/mm
• Large 65 mm x 17 mm Clear Aperture
• Determine Resolution, Field Distortion, and Parfocal Stability in an Optical System
• Low-Reflectivity, Vacuum-Sputtered Chrome on Soda Lime Glass
• Compatible with our MLS203 Microscope Stages via MLS203P2 Slide Holder

Thorlabs offers Ronchi ruling targets with resolutions ranging from 10 line pairs (one light line and one dark line) per millimeter (lp/mm) to 350 lp/mm. These square wave, constant-interval bar and space patterns are fabricated from the deposition of a dark low-reflectivity chrome pattern on a 3.00" x 1.00" x 0.06" (76.2 mm x 25.4 mm x 1.5 mm) soda lime glass substrate. This leaves a large 65 mm x 17 mm clear aperture, and works well in back-lit and highly illuminated applications. The dimensions of the glass substrate are the same as a standard microscope slide. These Ronchi rulings are excellent for evaluating resolution, field distortion, and parfocal stability in optical systems.

Click to Enlarge
Close Up of the Smaller Grid on the R3L3S5P Target with Labels Added (See Tables Below)

Click to Enlarge
Close Up of Entire Pattern on the R3L3S5P Target

• Concentric Circles and Crosshair Patterns Arranged in a Grid
• Four Different Concentric Circle Sizes and Five Different Crosshair Sizes
• Measure Resolution and Distortion of an Imaging System
• 3" x 3" (76.2 mm x 76.2 mm) Soda Lime Glass Substrate

Thorlabs' 3" x 3" (76.2 mm x 76.2 mm) Concentric Circle and Crosshair Grid Target offers 289 individual grids, arranged in a larger, 2" x 2" grid of 17 rows and 17 columns. The smaller grids each have four concentric circle patterns and five crosshair patterns of varying sizes. The concentric circle and crosshair patterns on the smaller grids are labeled in the image to the right but not on the target itself. Each concentric circle pattern features seven different radii, while the crosshairs each have a single or a double cross. For details on the dimensions of these patterns, see the tables below.

The pattern on this target is made made by plating low-reflectivity, vacuum-sputtered chrome on a 0.6" (1.5 mm) thick soda lime glass substrate to achieve an optical density of ≥3.0 at 430 nm. The dark pattern and clear substrate are useful for front-lit and general applications.

Click to Enlarge
Microscope Image of the R1S1L1N Negative Test Target

• Determine Resolution of an Optical System
• Measure Image Distortion, Astigmatism, and Other Aberrations
• 18 mm (0.71") Square, 1.5 mm Thick Soda Lime Substrate
• Includes 1951 USAF Pattern, Sector Star, Concentric Circles, Grids, and Ronchi Rulings
• Positive and Negative Targets Available

Thorlabs offers positive and negative 18 mm x 18 mm x 1.5 mm combined resolution / distortion test targets that are made by plating low-reflectivity, vacuum-sputtered chrome with an optical density (OD) of ≥3.0 at 430 nm on a soda lime glass substrate. They are ideal for the calibration of imaging systems and microscope stages.

The test targets include a 1951 USAF pattern (Groups 2 - 7), a sector star, concentric circles, grids (100 µm, 50 µm, and 10 µm), and Ronchi rulings (30 - 150 lp/mm). These targets are useful for testing resolution, field distortion, focus errors, and astigmatism. The 1951 USAF targets are useful for measuring imaging resolution. The grids can be used to measure image distortion, while the concentric circles are ideal for identifying focus errors, astigmatism, and other aberrations existing in an imaging system. The Ronchi rulings are excellent for evaluating resolution, field distortion, and parfocal stability. For more information, please see our Resolution Targets page.

These resolution targets are offered in positive and negative versions. The R1L1S1P positive target consists of a low-reflectivity chrome pattern plated on to a clear substrate and is useful for front-lit and general applications. Alternatively, the R1L1S1N negative target uses the same low-reflectivity chrome coating to cover the substrate, leaving the pattern itself clear, and works well in back-lit and highly illuminated applications.

• Line Pairs per Millimeter

• 3" x 1"  (76.2 mm x 25.4 mm) Soda Lime Substrate
• Includes NBS 1963A Pattern, Sector Star, Concentric Circles, Grids, Ronchi Rulings, and More (See Table Below)
• Determine Resolution of an Optical System
• Measure Image Distortion, Astigmatism, and Other Aberrations
• Compatible with our MLS203 Microscope Stages via MLS203P2 Slide Holder

Thorlabs offers positive 3" x 1" x 0.06" (76.2 mm x 25.4 mm x 1.5 mm) combined resolution / distortion test targets that are made by plating vacuum-sputtered low-reflectivity chrome with an optical density (OD) of ≥3.0 at 430 nm on a soda lime glass substrate. They are ideal for the calibration of imaging systems and microscope stages. They are sized to fit in our MLS203P2 stage slide holder for use with our MLS203 microscope stages.

The test targets include an NBS 1963A pattern, a sector (Siemens) star, concentric circles, grids, Ronchi rulings, and more (see table below). These targets are useful for testing resolution, field distortion, focus errors, and astigmatism. The NBS 1963A, sector star, and concentric circle targets are useful for measuring imaging resolution. The grids can be used to measure the distortion introduced by an imaging system. The Ronchi rulings are excellent for evaluating resolution, field distortion, and parfocal stability. For more information, please see our Resolution Targets page.

• The unit lp/mm is line pairs per millimeter.