Hi ImFusion Support,
When starting a 3D Freehand Ultrasound workflow, the probe is paired to the first listed tracking target.
Based on the image below, the tracked position looks to be attached to the center of the US image.
Which axis of the tracking target local coordinate system is going from the tracking target to the probe?
Is there any way to display it?
Thank you,
David
Hi,
Indeed, matrices always attach to the center of an image in our framework. Thus, the calibration of an ultrasound sweep is the transformation from the center of the US image to the tracking target.
Since you have access to the SDK documentation, you can have a look at the the page “General Design Documentation / Coordinate Systems”.
US images are assumed to be oriented as follows: the X axis stretches from the center of the image to the right, the Y axis downward, i.e. in the direction of the ultrasound beam. Z is this orthogonal to the plane.
I see that you have already found the Tracking Stream Visualization. You can also use the Tool Visualization algorithm: By default, it adds a needle mesh pointing into the Z direction. Rotations of (0, 90, 0) and (90, 0, 0) will align it to the X and Y axes, respectively.
Best,
Oliver
Hi Oliver,
When we rotate our probe around X or Z axis, the result in ImFusion is that the center of the rotation is the center of the US image.
What should we do in order to get the rotation occurring at the tip of the probe?
Thank you,
David
Hi,
As stated above, all matrices attach to the center of an image by default. You must use the calibration matrix translation to shift to some other point, e.g. half the image depth in y for setting it to the tip of the probe.
Best,
Oliver
