build texture options and orthophoto export

[Helsky]

Dear Agisoft team,

I have a view questions mostly regarding the build texture options related to multi.tiff images  (Photoscan Version 1.0.4 (64 bit) professional):
1.   I read in the forum that “Textures inside of Photoscan is stored in 8 bit (http://www.agisoft.com/forum/index.php?topic=177.msg723#msg723). Is this still valid and does this mean, that there is no reason to import images with more than 8 bit color depth (per layer/band)?
2.   I’m using areal images to reconstruct the 3D structure. However, I’m mostly interested in the near planar surfaces within the 3D topography when it comes to the real color representation within my multi.tiff bands. In the manual I read for the Texture mapping modes that (adaptive) orthophoto mapping “produces … more compact texture representations … for near planar scenes …”. What do you mean by “compact” - does this mean the quality is improved or reduced?
3.   Regarding the texture size/count: I don’t entirely understand the description here: Say I have image data in 1 cm ground resolution of a 50 m by 50 m area. If I would like to keep that resolution for my texture I would have to set the pixel size to 5000? Does the count influence the export image, since it is not shown in the Export Orthophoto window?
4.   And a bit more general: How can I derive the true resolution of my DEM & Orthophoto? Is this given by the Ground resolution data in the processing report?
Thank you very much.

[Alexey Pasumansky]

Hello Helsky,

Already two years have past since that topic. PhotoScan is already using full color range of the images.
But I think that you have mixed several questions into the single topic, so I'll try to underline some important points related to your questions.

A) Texture generation and orthophoto export are independent processes. Orthophoto generation doesn't take into account previously create texture, even the model can remain untextured up to orthophoto export step.
So mapping modes used in Build Texture dialog shouldn't bother you, unless you are interested in producing textured mesh model as output.

B) Texture size and count parameters defines the pixel dimensions of the texture atlas and number of texture atlas pages (the latter is only applicable for Generic mapping mode).

C) Multichannel TIFF images with four and more channels in the version 1.0.4 are treated differently from the common three-band images. At first user defines Master Channel in the chunks' context menu in the Workspace pane, that will be used for the alignment stage and dense cloud generation stage (also note that texture generation cannot produce multichannel texture atlas and only Master Channel will be used).
But at the Export Orthophoto stage, if TIFF format is selected, the resulting ortomosaic will contain all the original channels.

[Alexey Pasumansky]

Here are examples of generic, orthophoto and adaptive orthophoto mapping modes for texture generation: