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Kai

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  1. Sorry for the 9 month delay, we had to stop our project, but now we have time to pick it up again. Thank you very much for your replies, you helped me a lot to understand the different aspects. I think i might come up with a couple of other, more practical, questions in the next weeks.
  2. Hi, this is my first topic, so hopefully it is at the right place and sorry for all grammar and spelling mistakes. We use the highlight method for a few weeks for our palaeontological research and we want to publish our results. However it is much easier to use the method than to understand the details (I have no backround in physics or photos what so ever). Therefore I want to ask the experts if my understanding of the method is correct and if you could explain me the difference between hsh and ptm. What I (think I) got so far is: Usually a pixel contains color information (RGB) in a ptm published by Malzbender et al. (2001) each pixel has additional information about the luminescence (=reflectance??; =shape/relief??), stored by the coefficents a0-a5. Therefore a PTM contains information which makes it able to show how the light would reflect from each pixel, making it an image with movable light source (simply spoken). The first data were .ptm as developed by malzbender, while the "new generation" is the .rti data, which is based on different algorithms. This was developed by the CHI (?) whit a focus on better refelctance but with the lack of other features. Does this new algorithm use the same method as the ptm (storing additional surface data to each pixel)? Is hemispherical harmonic a different approach than ptm? Is hsh only a different algorithm? Do you have any papers regarding the hsh? I only found a very short mention in Mudge et al. (2008) with the picture of a coin used to compare ptm and hsh. And a paper of Wang et al. "Material Classification using BRDF Slices", however I am not sure if this is related to RTI... Reflectans transformation If I understood Hammer et al (2002) correctly: "diffuse gain and specular enhancement are both methods of reflectans transformation", which would mean reflectans transformation is a method (?) to change the reflectance of an object, which is possible due to the additional data in a ptm. Ufff so many questions and so limited understanding of image capurting and processing.... Thank you very much for your help Kai p.S. I will opend another topic with other questions in the highlight method forum.
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