Angle measurement range

Support
1

Hello, the calculated values for both angles here are 0-90 degrees. Is there a way to change the range of values to 0-180 degrees in 3d?

2

Not entirely sure what you mean. You can have angles >90 degrees…

image
image1552×710 53.4 KB

3

I split the topic because I interpreted the same way it as you @muratmaga but I’ve read it again and realized that maybe @learn_shape refers to the C-arm angles?

Those angles are defined in DICOM. The primary positioner angle is indeed allowed to be in the +/-180deg range, while the secondary angle is always between +/-90deg. You can get the +/-180deg range if you switch to use atan2 in the script. The end result will be something like this:

    nx = viewNormal[0]  # R
    ny = viewNormal[1]  # A
    nz = viewNormal[2]  # S
    import math
    if abs(ny) > 1e-6:
      primaryAngleDeg = math.atan2(nx, -ny) * 180.0 / math.pi
    elif nx >= 0:
      primaryAngleDeg = 90.0
    else:
      primaryAngleDeg = -90.0
    secondaryAngleDeg = math.asin(nz) * 180.0 / math.pi
    return [primaryAngleDeg, secondaryAngleDeg]
9

In the image above the patient coordinate system is left-handed. In DICOM, patient coordinate system is right-handed (LPS). Therefore, it is quite likely thay you have fed wrong input to the code snippet.

10

sorry,i am a student. your code can match the body position(A P L R H F)？for example ，when body position A, lao/rao is 0 degree, and cra/cau is 0 degree

11

DICOM names for patient coordinate system axis directions are anterior, posterior, left, right, superior, inferior.

Patient position is generally assumed to be head-first-supine on the C-arm table.
Primary and secondary positioner angles refer to the viewing direction (orientation of the C-arm).

12

but in fact the secondaryAngleDeg is allowed to be +/-180. in C arm. I wanted to modify your code to achieve an angle above 90 degrees, but it failed.

13

Secondary positioner angle field cannot go beyond +/-90 degrees. See the DICOM standard.