camera.xml

[dze]

Hi
does someone have any documentation explaining the different fields/parameters in camera.xml file?
Regards

[dze]

Any help please?

[Alexey Pasumansky]

Hello dze,

Do you mean export cameras or export calibration output?

Maybe you can post a sample to be more clear?

[dze]

Hi Alexey

the file I'm talking about is the following
<?xml version="1.0" encoding="UTF-8"?>
<chunk>
   <sensors>
      <sensor id="0">
         <property value="some value" name="pixel_width"/>
         <property value="some value" name="pixel_height"/>
         <property value="some value" name="focal_length"/>
         <property value="false" name="fixed"/>
         <calibration type="frame" class="adjusted">
            <resolution height="...." width="...."/>
            <fx>"fx value"</fx>
            <fy>"fy value"</fy>
            <cx>"cx value"</cx>
            <cy>"cy value"</cy>
            <skew>"skew value"</skew>
            <k1>"k1 value"</k1>
            <k2>"k2 value"</k2>
            <k3>"k3 value"</k3>
            <p1>"P1 value"</p1>
            <p2>"p2 value"</p2>
         </calibration>
      </sensor>
   </sensors>
   <cameras>
      cameras details ...
   </cameras>
   <ground_control>
      ground control  ....

Regards

[Alexey Pasumansky]

Hello dze,

This xml file represents the same information you can find in the Camera Calibration dialog.
pixel_width, pixel_height and focal_length are usually derived from EXIF and are estimated in mm. These values are used for correct Initial guess for autocalibration procedure.

Other parameters inside the <calibration> tags refer to the camera intrinsic parameters. The calibration model is described in Agisoft Lens manual, but in brief:
fx, fy - focal length in pixels,
cx, cy - principle point coordinates in pixels,
k1, k2, k3, k4 - radial distortion coefficients,
p1, p2 - tangential distortion coefficients.

[dze]

Thanks Alexy, your post was helpful

I had a look to Agisoft Lens manual, now its is clear for calibration tags.

do you have any manual/document describing the following tags
<cameras>
     <resolution ....>
     <transform>     ....   </transform>
      cameras details ..
</cameras>
<ground_control>
      ground control
</ground_control>
<transform> </transform>
<reference> .... </reference>
<region>
    <center>... </center>
     <size>...</size>
     <R> ... </R>
</region>

what is the difference between the transform tag in cameras tag and the transform tag?
Regards

[Alexey Pasumansky]

Hello dze,

4x4 matrix under camera section is related to the camera position and orientation in the internal coordinate system, and the isolated transform section contains 4x4 matrix that describes transformation between internal coordinates and system used for referencing (when chunk is referenced).