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RE: VERY large images of microscope slides.
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RE: VERY large images of microscope slides.



On Tue, 20 Feb 2001 tom smith <email@hidden> wrote:

>I have been asked to look at the feasibility of using quicktimeVR to present
>microscope slide images. The images are VERY big (they use a special
>camera), allowing students to roam and zoom in, looking for anomalies.
>
>Small quicktimeVR versions of the images have been proven to work well.
>http://213.38.36.15:8080/otherscope/original_slide
>
>But as soon as the images get big, I run into problems.
>
> size                                          4072 x 2712 pixels
>BMP source file                        197.4 MB
>saved as JPEG 50% quality      8.4 MB
>saved as JPEG 0% quality        1.3 MB

-----------------------------------------------
Tom,

I think I'm missing something here - my calculations indicate an image with
a  (4072 x 2712) pixel dimension should be 31.6 megs in size; a file with
that same aspect ratio pumped to 197.4 megs would be (10,152 x 6,793)
pixels in size.

VR Worx 2.0 will allow panos with dimensions up to 3,000 pixels high x
10,000 pixels wide which would handle the (4072 x 2712) pixel size you gave
in your specs.

Assuming that I missed something on the pixel/file size relationship, why
not simply create several panos:

* Master Pano -One with a general overview of the whole image (which would
still show a lot of detail with a 32 meg file)

* Detail panos - Divide the large 197.4 image divided into 6 sections with
a nice overlap.
When zoomed in on a pano and panning to an edge, hot spots on the edge
would take you to the next node (section) in the corresponding place. By
placing a series of linear hot spots along a given edge you could maintain
a reasonable amount of control over where the viewer ends up in the next
node without a disorienting jumping around.

* Once you have created one of these multinode scenes. You can save it as a
template and simply swap in and out whatever group of pictures you want
(assuming the new images have the same resolution/pixel size).

* The collection of smaller images would be less demanding on the viewer's
hardware/software set-up.

This problem seems to have generated some interest, I certainly haven't
worked with a single image in the 200 meg range for QTVR work. It will be
interesting to hear what ends up being a good solution for you. Good Luck!

Jim Scott




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