Imatest-Furonteer Geometric Calibration Solution

Imatest-Furonteer Geometric Calibration SolutionThe Imatest-Furonteer Geometric Calibration Solution enables companies to understand the images captured from their devices. This solution calibrates as-built camera systems by accurately mapping the pixel position to real-world positions for monocam, stereo pair, and multicamera devices. Imatest combines the analysis software and calibration hardware required for rapid testing in a production line.

Imatest and Furonteer engineers optimize each test setup for your specific camera(s), and actuators enable automated camera manipulation to calibrate camera systems. Our engineers have successfully produced a high-throughput solution for devices with fields of view between 28° and 155°.

Key Features

  • Calculate intrinsics, extrinsics, and distortion.
  • Test single and multicamera systems.
  • Free-space test within minimum focus distance.
  • Conduct tests in 30 to 90 seconds.
  • Calibrate a range of fields of view.
  • Automated testing.
  • Integrated software analysis.

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Why Use a Test Machine?

Talk to an Engineer

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Dynamic Range Test Charts

    

Patch_Dynamic_Range charts

36 Patch Dynamic Range (LDR)

  • At least 50 dB of Dynamic Range
  • Gray background for proper auto-exposure
  • Slanted edge and color patch features

ITHDR36_preview

GrayWorld WDR & UHDR

  • At least 100 dB or 150dB of Dynamic Range
  • Constructed from two and three layers of photographic film
  • Gray background for proper auto-exposure
  • Characterize real-world system performance

Contrast Resolution

  • Measure distinguishability of low contrast objects within larger fields with Imatest 5.0
  • 100 dB of Dynamic Range
  • Grey background for proper auto-exposure
  • Slanted edge features

DarkWorld Mask

  • Goes over 36-patch test charts
  • Idealized dark scene with minimum flare
  • May be difficult for autoexposure

XYLA

  • Dark background with linear steps
  • 84 dB, 120 dB or 150 of Dynamic Range
  • Includes self-contained light source
  • Difficult to detect, affected by light falloff

ISO 21550

  • Optical density 4 to 6
  • Supports the ISO standard
  • Good for macro systems
  • Low cost

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Lightbox Comparison Guide

 

Lightbox Brightness Uniformity* CRI (spec.)
Viewing Area Dimensions Controls
ITI LED Lightbox 30 – 10,000 Lux 95.2% Over 97 260 mm x 220 mm 400 (W) x 380 (H) x 100mm (D) Bluetooth, USB
IQL LED Lightbox 10 – 40,000 Lux     254mm x 279.4mm 472.4 x 383.5 x 129.5mm Wireless via Android
GL-16e Lightbox Viewer 5750 Lux 63.6% 96-98 10 x 18″ (25 x 46 cm) 15x25x5″ (38x64x13cm) Manual
GL-20e Lightbox Viewer            
GL-30e Lightbox Viewer            
GL-44e Lightbox Viewer            
GLX-3044 Lightbox Viewer N/A N/A 96-98 30×42″ (76x107cm) 35x49x5″ (89x124x13cm) Manual
GLX-3856 LIghtbox Viewer N/A N/A 96-98 38×56″ (96x142cm) 43x63x5″ (109x160x13cm) Manual
GLE-10 Lightbox Viewer N/A TBC 96-98 8×10″ (20x25cm) 15.5×12.25×3.25″ (39x31x8cm) Manual
GLE GLX-30 Lightbox Viewer 5000 Lux 70.1% 96-98 16″ x 30″ (41 x 76cm) 21 x 37.5 x 5″  Manual
Artograph LightPad® 930 2820 Lux  77%   12×9″   On/Off
Artograph LightPad® 950 2740 Lux 78.5%   24×17″   On/Off

*measured using 9 rectangular regions, as described below.

 

A better color quality measurement?  The color quality of light sources is traditionally measured by CRI (Color Rendering Index), which has a maximum value of 100 (%). Recently, doubt has been cast on the accuracy of CRI, and a new Color Rendition measurement has been proposed: IES TM-30-15. It’s unfamiliar and the linked document doesn’t have an equation or algorithm for calculating it from the light spectrum. We’ll wait and see…

Lightbox Uniformity- Detailed Measurements

For the key measurement, the definition of uniformity is

Uniformity = 100%*(1 – (maximum of 9 regions- minimum of 9 regions) / maximum of 9 regions)

where the 9 rectangular regions (shown in the figures below) include the top, bottom, left, right, 4 corners, and center. The rectangular region dimensions are 10% of the crop width and height and (except for the center region) they are located 5% of the width and height from the boundaries, as described below.

 

Click on any of the images below to view full-sized.

ITI LED Lightbox

Uniformity = 95.2%

Response is very even, but unusual in that the center is slightly dimmer than the top and bottom.

Note that the contour line increments are 0.01 (1%), lower than the other lightboxes because the ITI is much more uniform. (0.02 contour increments wouldn’t show very much.)

The lightbox spectra for the standard 3100K and 5100K settings, provided by ITI, are shown below.

ITI_uniformity_contours
ITILED-3100k ITILED-5100k

GTI GL-16e Lightbox

Uniformity = 63.6%

The contour line increments are 0.02 (2%), double that of the ITI LED Lightbox. Both the GL-16e and GLX-30 have very wide aspect ratios. Their uniformity would be much better if less of the sides were included in the measurement.

 

GTI_GLX16e_uniformity_contours

   

Artograph 930 12×9 inch Light Pad

We use this inexpensive lightbox for non-critical applications like MTF measurements and for trade show demonstrations. It’s uniformity is quite good.

Uniformity = 77%

Artograph_12x9_uniformity_contours

Artograph 950 24×17 inch Light Pad

We use this large, relatively inexpensive lightbox for non-critical applications like MTF measurements and for trade show demonstrations. It’s uniformity is quite good.

Uniformity = 78.5%

(Figure is darker because image was less exposed.) 

Arto_950_uniformity_contours

The control

The control for these measurements was made by capturing images immediately in front of the ITI lightbox (no more than 1cm distant). Results were repeatable when the camera was moved around the lightbox. Contour increments are very small: only 0.002 (0.5%).

Uniformity = 98.75%

EOS-6D_closeup_uniformity

GTI GLX-30 Lightbox

(No longer available in the Imatest Store)

Uniformity = 70.1%

The contour line increments are 0.02 (2%), double that of the ITI LED Lightbox.

GTI_GLX30_uniformity_contours

GTI GLE 12e Lightbox

(No longer available in the Imatest Store)

Uniformity = 65.8%

The contour line increments are 0.02 (2%), double that of the ITI LED Lightbox.

GTI_GLX12e_uniformity_contours

How we made the measurements

We developed a methodology for measuring lightbox uniformity because we were not aware of any relevant standards.

  • Photograph the lightbox using a camera with a long focal length marco lens. Such lenses tend to be highly uniform, i.e., have very low vignetting. We used the Canon EOS-6D with the highly-regarded 100mm f/2.8 macro lens set at f/8. Be sure to capture raw images. We used manual focus because the EOS-6D didn’t focus well on this image.
  • Frame the lightbox so it occupies about the central 30% of the image (10% by area). This makes the already low vignetting insignificant. Here is the framing (and region selection) for two lightboxes.
Click on the images to display them larger.
ITI_uniformity_cropITI Lightbox GTI_uniformity_cropGTI Lightbox
  • Open Uniformity (or Uniformity Interactive) and read in the raw file, converting it to a gamma = 1 (linear) file. (This means it’s not a standard file, but pixel level will be proportional to illumination.) Here are the recommended settings from the Imatest dcraw GUI window. The key settings are Output gamma = 1.0 (Linear), Auto white level checked, and Normalize by 1.0.

lightbox_dcraw_settings

  • Crop the images just inside the bright areas of the lightbox, as shown above. If there are areas of rapid illumination falloff close to the edges of the lightbox image, it’s OK to omit them.
  • Click Yes to open the Uniformity settings box. The key settings are shown inside the red rectangles. The corner and side regions (the rectangles) are 10% of the ROI (linearly), and the location of the regions is 5% (of the ROI size) from the ROI boundaries. We feel this is a reasonable summary metric since most tone and color measurements are made in the central two-thirds of the image. Uniformity is more important when measuring tone and color than it is for MTF, even though Imatest corrects for patch nonuniformity due to vignetting and uneven illumination.

lightbox_uniformity_settings

  • After you click OK (not shown) Uniformity runs and the results figures appear. The key nonuniformity summary metric does not appear in the figures it’s in the CSV and JSON file output. Here is the relevant CSV output.

    Uniformity = 100%*(1 – (maximum of 9 squares – minimum of 9 squares) / maximum of 9 squares)

Nonuniformity LRTB sides ctr (%) 36.44
Uniformity LRTB sides ctr (%) 63.56
  • and here is the JSON output:

         “nonuniformity_LRTB_sides_ctr_pct”: [36.4],
         “uniformity_LRTB_sides_ctr_pct”: [63.56],

 

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Imatest Studio

Your test lab is more than just a camera and software.

 

Imatest offers more than just software for testing lenses and cameras. From printers to individual users, Imatest has everyone covered.

 

Imatest Studio:

  • Scaled back version of Imatest Master for individuals.
  • Allows photographers to better test their professional camera without breaking the bank on software.
  • Contains many of the same proprietary, sophisticated features as Imatest Master.

Regular License $299.00

Download free trialWindows & MAC
English

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Gamutvision

Gamutvision is a color gamut viewer that allows you to explore the behavior of ICC profiles —
files that characterize color spaces and/or device behavior (cameras, printers, monitors, etc.).

Gamutvision is particularly well suited for visualizing gamut mapping — changes in color and tone when images are moved between files and devices with different color response. It is a powerful tool for learning color management and proofing color workflows.

Starting in November 2022, it is available as a module of Imatest (Studio and Master) in the 23.1 pilot program. If there is sufficient customer interest, we may release it as a standalone product.

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ISO Standard Test Charts

Manufactured to exacting standards

 

Our ISO charts meet all ISO standards for image quality requirements on imaging devices.

 

Anatomy of the eSFR ISO Test Chart:

Watch on YouTube.
  • Meets international standards. The International Standards Organization (ISO) for Photography sets the international standards for image quality analysis and all of our charts conform to the specifications set by the ISO Committee.
  • Compatible with Imatest software. All ISO charts work with Imatest Master and IT.
  • Perfectly calibrated, high resolution print quality. Printed on our expertly calibrated printers, you can trust that each chart will produce the same result as the last.

Our Most Popular ISO Standard Charts:

  • Photographic ISO 12233:2014+ eSFR
    With high-precision photographic printing, this chart enables optimal testing for high-resolution sensors as well as compact macro tests.

  • ISO 18844 Flare Test Target
    Backlit target made on high contrast mylar film for testing Flare as outlined in ISO 18844. Assembled with low reflectance patches.
  • Inkjet ISO 12233:2014+ eSFR
    Our chart closely resembles the implementation of the Low Contrast eSFR test chart illustrated in ISO Standard Document. We have made a few key enhancements to our version to maximize analysis capabilities.
  • ISO 15739
    This 15-patch grayscale step chart has 12 of the patches in a somewhat elliptical arrangement on the periphery and three in an inside row. It is supported by the Imatest Stepchart, Multicharts and ColorTest modules and fully supports automated region detection. The chart is printed on 12x18 inch (305x457 mm) luster inkjet media.
  • ISO 21550
    Small film target designed for testing Dynamic Range of Electronic Scanners for Photographic Images. Two variants are available with densities ranging from 0.1 to 4.0 or 0 to 6.0. 
  • ISO 14524
    This chart features 12 gray levels on a durable material. Densities range from 0.10 to 2.30 and it is available on luster photographic paper or inkjet media. This particular chart fully supports automated region detection.
  • See all ISO Charts

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SFRplus

Automated image quality analysis

 

Our proprietary, ISO-compliant SFRplus charts are designed to work with Imatest software to provide automated, comprehensive image quality analysis.

 

  • Less wasted area: SFRplus charts make use of the entire chart space, while only about 10% of the standard ISO chart area provides useful information for computerized analysis.
  • Reduced clipping of high-contrast edges: Making SFRplus test charts more accurate and consistent and less affected by overexposure and underexposure.
  • More signal processing information: Allowing measurement of the effects of signal processing, such as sharpening and noise reduction that you would not be able to collect with an ISO chart.
  • Automated Region Detection: Automatically identify regions of interest without manual input.
  • Variety of sizes and substrates: From 5 x 5 cm to 110 x 187 cm, printed on Matte, Semigloss, or Backlit Media (DisplayTrans) or Photographically Printed Charts on paper or film and even chrome on glass targets for the highest precision needs.

SFRplus tests for:

  • Noise
  • ISO Sensitivity
  • Color Accuracy
  • Texture Response
  • Distortion and Geometry
  • Resolution and Sharpness
  • Gamma and Tonal Accuracy
  • Lateral Chromatic Aberration

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