Measure OTF of the lens-sensor system

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This is a legacy page. Information may not reflect the current state of the products or code. See more about lens measurements on Elphel Blog: Category:calibration


  • Install ImageJ.
  • Get plugin from GIT and compile it in ImageJ.
1.1. Copy the source to the "Plugins" folder of the ImageJ installation
1.2 Launch ImageJ
1.3 Drop down menu "Plugins -> Compile and Run..."

2.1 It might be useful getting the following plugins as well: - converts JP46 - can generate simulation pattern

Test Pattern

Print the test pattern (A) or generate it (B).

A - print

  • The stripes on the paper are vertical of course. But there should be a small angle on the test image.
  • Each stripe width on the test image should be not less than 32 pixels
  • The minimum is 3 stripes: BWB or WBW.
Test Pattern

B - generate

  • Get - compile and run
  • Click Create Color Pattern
  • Choose Pattern Type
  • Set Nonlinearity to 1 (square)
  • Set the stripes period (each stripe width on the test image should be not less than 32 pixels)
  • OK - the plugin generates only RED, GREEN or BLUE stripes - so it will be like color filter. RED will be ok.

Camera Settings

Gamma 1.0
Black Level 0.0
Color Saturation 0.0
Image Quality 100%
Color Sensor Mode Mono
Set the Color Sensor Mode to Mono only when Color Saturation is 0.0


1. Save the image of the test pattern.

2. Launch ImageJ - open the saved image and launch the plugin

MTF Bayer plugin interface

3. Select the area of the measurement.

 Should contain at least 2 edges - 1x Black-to-White & 1x White-to-Black but the more edges in the area of interest the better

4. Process - the MTF chart will be shown

Change the image type in ImageJ to 32-bit if you are getting an error: drop-down menu Image -> Type
Result chart: the MTF curves are drawn for all 4 color channels for BW and WB edge (8 as a result): RED - red curve, GREEN (from RGR line) - light blue curve, GREEN (from GBG line) - green curve, BLUE - blue curve

5. Show MTF text for spreadsheet use.


  • The higher curve the better.
  • Normally the blue channel has the worst curve.