Interpolator - function and wrong workflow

Specific Q&A about the new Flash export
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360Texas
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Tue Dec 12, 2006 8:39 pm

Hi I just learned what Lanczos interpolator does and realized that I was applying it 2 times to the same panorama in my work and that was what was causing image degrading.

The Lanczos interpolator is an algorithm that is used to sharpen an image. As we know over sharpening an image causes all types of issues.

This page was written in 2003. Paragraph 3 shows how the original pixel is resampled using the different types of interpolators. Paragraph 7 Conclusions gives some interesting suggestions about which interpolator to use. Alot of the in between explanation is way over my head.

http://www.ast.cam.ac.uk/vdfs/docs/reports/interpol/


I was using Lanczos interpolator while stitching 16bit TIF in PTgui.

I was using Lanczos3 interpolator while using Pano2QTVR to cube, (fix the tripod cap) then back to equilateral image. And again to convert to Flash or QTVR final image. Using Lanczos3 was taking 4 minutes to do these conversions.

The resulting Flash or QTVR file.. rendered with zone blur artifacts and sharp areas. Some areas appeared sharp and other areas were blurred. I tried to use zone sharpen tool to clean up the blurry areas.. but in the end I just made a mess of the image.

So today Markus in Switzerland and I reviewed my work flow.. and determined that we were WAY over sharpening by the repeated use of Lanczos interpolator.

I went back to my original 60+mb original 16bit TIF sitched images... and opened each one in Pano2QTVR.. found the optimum tile size, and used Spline36 interpolator. The Spline36 took only 15 seconds not 4 minutes to render which permitted me to quickly repeat the convert to flash .swf file size of 1.0 +/- mb output while maintaining the high degree of sharpness.

If you have not already done so.. please again visit

http://www.360texas.com/virtualtour/tex ... /index.htm

Ahh but you already knew all about this and just forgot to tell me.
Dave
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