<br><br>Hi Dan,<br><br>The origin is expected to be in the lower left corner of an image and it is<br>expected to be expressed in physical coordinates (not pixels),<br>e.g. millimeters or centimeters.<br><br>Note that the notion of "left / right" and "upper / lower" is
<br>a *VISUALIZATION* notion.<br><br>What appears on your screen up or down, and left or right, depend on <br>what image viewer you are using..<br><br>We will strongly encourage you to use a viewer designed for medical applications,
<br>not a generic viewer such as the default fax viewer that you get on Windows, or<br>the generic display from ImageMagick.<br><br><br>You will find a minimalistic viewer in the InsightApplications/ImageViewer directory.
<br>You can also download Windows binaries of this application from :<br><br> <a href="http://public.kitware.com/pub/itk/InsightApplicationsBin/">http://public.kitware.com/pub/itk/InsightApplicationsBin/</a><br><br><br>
In order to make sense of the conversions between indices and physical coordinates<br>you must start by printing out the details of your image using<br><br> image->Print( std::cout )<br><br>and gathering the information about:
<br><br><ul><li> image origin</li><li> pixel spacing</li></ul><br>Note that some images may indeed have negative spacing,<br>and/or negative origin values.<br><br><br>Regards,<br><br><br> Luis<br><br><br>
-------------------------------------------------------------------------------------------<br><div><span class="gmail_quote">On 7/9/07, <b class="gmail_sendername">Dan Homerick</b> <<a href="mailto:danhomerick@gmail.com">
danhomerick@gmail.com</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">A hopefully very quick question -- should the origin be set to the physical coordinates of the upper left corner of the image, or the lower left corner?
<br><br>I would assume upper left, but the diagram in the Software Guide seems to indicate lower left. If it specifies in the text anywhere, I must be overlooking it.
<br><br>I keep getting negative numbers when I use image->TransformPhysicalPointToIndex, and while it's probably a bug somewhere upstream in my code, if anyone knows of a common mistake that will cause that, please let me know.
<br><br>Cheers,<br><span class="sg"> - Dan<br>
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