MAF3 with Cross Polarization Filter and external ligth

• CG

  Christian Gassner

  12/29/25, 7:38 PM

  I have done some basic testing using cross polarization with MAF3.

  I am using this for photogrammetry and to me this is the holy grail to get outstanding texture quality.

  Cross polarization requires external lights where polarization between light and cameras are crossed by 90°.

  This helps to reduce light reflection on the object (white spots). Especially for bright objects this can be big problem. Most professional photogrammetry experts are using DSLR with ring flash and cross polarization.

  I am sharing this idea here in the forum to see if there is any willingness from dev team to support such expert features in the MAF3 software. It's not rocket science but HDR and use of external lights (with or without cross polarization) would require some processing options to make it easy to handle. At least running custom macro to define sequence of commands with different exposure setting for point cloud scanning and texture capturing would be needed.

  Feedback and discussion about this idea .... welcome!

  MAF3 and external lights equiped with polarization filter. Polarization from ligths and cameras are crossed by 90° to reduce light reflection a lot.

  

  Without cross polarization lot of reflections visible!

  

  With cross polarization used, the reflections are reduced a lot ... almost completely eliminated!

  

  GIF animation is showing the difference when changing the polarization filter on the MAF3 cameras from non-crossed to crossed position.

  

  I believe that use of external light (with and without cross polarization) and HDR support could boost the texture quality a lot and make MAF3 to a real differentiator compared to competition. The HW design from MAF3 supports such optimizations, but they will require some additional software support and updates. I am hoping to see support in later SW versions and to have some interesting discussions on the topic.

   

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• TM

  Tom Meeks

  12/30/25, 2:58 AM

  I am going to second a look at this potential solution to reflection of models for which scanning spray is just not appropriate.  I have a collection of tobacco tins from the 1950's that will never be produced again.  They are painted characters in a "Roly-Poly" shape.  Spraying would cover the character features and without spray the single light source of the THREE reflects in a tight little area.  Away from the center of the highlight reflection, the light falls off quickly.

  Now, it's not the most important scanning target; but, it would be nice to be able to capture these whimsical containers in full 3D for future generations.  And, this is true for all of the tin toys so popular in the 1940-1960 era.  Safety regulations killed the tin toy industry.  So, toys and containers of this type, that live beyond the 'junk' phase are destined to be rare antiques.  😊

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• CG

  Christian Gassner

  12/30/25, 8:46 AM

  After some further testing i come to conlusion that HDR is absolutely mandatory for high quality texture capturing with MAF3 cameras. This is valid also when using additional external lights (e.g. photo box).

  BUT ... when using HDR for texture with MAF3 cameras the image quality is outstanding! So much better compared to current implementation. It's must have feature to bring texture from MAF3 on next level.

  Texture quality out-of-the-box, without external lights, without HDR, without CP. Dark areas are under-exposed without lot of details. Increasing the exposure settings would lead to exceeding the saturation for white area because of low dynamic range of cameras. 

  

  Improved texture quality with external HDR processing (3x images, normal/over/under-exposed), without external lights, without CP. All images captured with in-build MAF3 cameras. The texture quality is much better and the color range is increasing a lot. Also dark areas are showing lot of details. Drawback still are the reflections (white spots) because of quite shiny surface. 

  

  Further improved texture quality with external HDR processing + external lights + cross polarization. Polarization filters added on MAF3 cameras and crossed by 90° to external LED lights. The texture quality is almost perfect. Light and dark areas are showing lot of details and reflections have been almost eliminated by use of cross polarization method. 

  

  I think the results speak for themself?

  It would be a big mistake to not implement HDR solution to MAF3 SW because the texture quality is improving a lot without changing anything on the HW.   

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