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leszekp

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leszekp last won the day on February 25

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About leszekp

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    Archaeology of the American Southwest and West.

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  1. leszekp

    Unknown Error Detected

    I have regularly had problems with the standard PTM fitter on Windows for images larger than 24 megapixels; it usually crashes. For all my PTM processing, I've switched over to using the new ptmfitter from Custom Imaging, available at https://custom-imaging.co.uk/. It can handle images up to 100 megapixels in size, and as a bonus it's a lot faster than the original HP fitter. On the downside, it won't work with RTIBuilder, so you'll need to create an lp file with RTIBuilder, and then use that with the new ptmfitter in command line mode.
  2. leszekp

    Processing in Multiple Locations

    I second Dave's advice. Even a cheap laptop (<$300) should be able to process RTI imagesets in a reasonable amount of time.
  3. leszekp

    Basic hardware

    If you're going to do SfM work, I'd recommend at least 32 GB of RAM, and as much as you can afford (though most motherboards can't take more than 64 GB). SSD drive for the boot and main work drive, at least 256 GB; regular hard drive for longer-term storage is fine. Definitely recommend nVidia for the graphics card, and get the fastest one you can afford; video RAM is not as important. Not sure you'll be able to upgrade your ToughBook, though.
  4. leszekp

    Photoscan Pro vs Photomodeler Scanner

    Haven't used PhotoModeler, so can't speak about it. Did the trial version of Pix4D, and results looked good, although the trial version didn't export in the highest resolution. I've mainly worked with Photoscan, both Standard and Pro versions, and have been very satisfied with it. Have done a number of archaeological drone projects with high-accuracy GCPs using RTKGPS, and have been very happy with the results in terms of accuracy. BTW, Photoscan is dead - it's now called MetaShape.
  5. leszekp

    RTI Viewer foriPad ?

    Used to be - unable to find any reference to it on the iTunes store.
  6. leszekp

    RTI Builder Unknown error

    The old ptmfitter had an effective image size limit of 24 megapixels on Windows, even on systems with lots of RAM. The new ptmfitter from Kirk Martinez' group has no problems handling images up to 100 megapixels in size; I don't go any higher because the RTIViewer software has problems above 100 megapixels. https://custom-imaging.co.uk/software/
  7. leszekp

    The Format of imported images

    Somewhere online there used to be a description of the ptm format, but that appears to have disappeared. It should be described in the original Malzbender paper about PTM. Don't know if I've ever seen anything comparable for the rti format, but the original paper about HSH fitting should give you some information. You might contact CHI directly for the source code for the hsh fitter, and that should give you information about the storage format for the rti files. Not sure exactly what kind of useful information you expect to get from the files. They just store the fitting coefficients for every pixel (along with the RGB date) that's used to calculate normals, both of which are used by the viewer to display the image and the effects of changing the lighting angle.
  8. leszekp

    The Format of imported images

    Both fitters (PTM and HSH) only take jpg files. If you have uncompressed images, you will have to convert them to jpg format. Just select the highest quality jpg setting for the best results. I convert RAW files to JPG format all the time, and they work fine.
  9. leszekp

    An alternative for controlling 3W leds

    I had noticed that it was somewhat conductive, probably because it's full of graphite. But didn't see any effects in my system.
  10. leszekp

    tiny objects

    You might also try stopping down even further to F11, to get a better depth of field. The other issue is whether the skull has enough details on it for Photoscan to be able to match points between different photos. If not, you might try shooting RAW, then increasing contrast/clarity in the photos to accentuate whatever details are present.
  11. leszekp

    Truvis

    Yours for the low, low price of $24,000 (not including camera). Or you can build your own for less than 5% of the cost: https://hackaday.io/project/11951-affordable-reflectance-transformation-imaging-dome
  12. leszekp

    Truvis

    Hmmmm... https://broncolor.swiss/scope/ https://truvis.ch/ For a brand-new breakthrough visualization technology, it looks awfully familiar ...
  13. leszekp

    The size of dome

    For lithics, I use the normals mode, then manipulate the RGB channels individually for maximum contrast. Convert to grayscale, do some more advanced contrast work (clarity/CLAHE), sharpen it up, and you get a fantastic image of the flake scars on the stone tool, better than any hand drawing.
  14. leszekp

    An alternative for controlling 3W leds

    Running the 3W LEDs continuously is definitely a bad idea when there's no heat sink. The solder melting point is less than 200C. They only need to be on long enough to take your photo, which shouldn't be more than a few seconds. While many of these are rated up to 1A, the usual nominal operating current is 700mA, at which current level they will stay quite a bit cooler. Intensity is a bit lower, and the exposure time will be slightly longer, but it's not going to be a huge different (a few tenths of a second).
  15. leszekp

    An alternative for controlling 3W leds

    I had the same thought a few years ago, but decided that it didn't make sense. You're fitting a curve to the (primarily) Lambertian lighting scattering at every point based on the lighting angle. If you change the lighting intensity with angle, you'll skew the lighting curve to fit to those higher intensities, which will introduce errors. Shadows are areas where the main light source is blocked, so any signal from those areas is a result of scattered light within the dome, which doesn't really offer you any useful signal for curve fitting.
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