CAHVOR_camera_model - Python Implementation

• Converting Photogrammetric Parameters to CAHVOR
• Converting CAHVOR to Photogrammetric Model
• Python Implentation of CAHVOR camera model and its photogrammetric conversion for planetary applications

Dependancies

• Python3
• Numpy
• math

CAHVOR model

• CAHVOR camera model details
• Photogrametric model details

Input Requirements

• pixel size
• Image Size

(NOTE: Deepending on the application, user must have EXTRINSIC and INTRINSIC camera parameters -OR- CAHVOR generated from Camera Calibration)

Usage

• Python3

  >>> from get_cahvor import CAHVOR
  >>> a = CAHVOR()
  >>> a.cahvor
  

  >>> import get_cahvor
  >>> print(model)  # model is dict type
  {'center': [3.451904, 3.258335, 1.254338],
  

'f': 29.4711992, 'image_size': [506, 762], 'pixelsize': 0.01838, 'principal': [-0.09574394, -0.11071695], 'rotation_mat': array([[-0.69620161, 0.71768083, -0.01541225], [-0.16672233, -0.14077498, 0.97590269], [ 0.698217 , 0.6819946 , 0.21766119]]), 'az': 90, 'el': 0}

a = get_cahvor.compute_CAHVOR(model) a

* command-line

$ python3 get_cahvor.py

Results
-------
$  python3 get_cahvor.py

---

Note: Enter Vector Elements Row by Row with Space in between

Enter Principal Point (x0, y0): -0.09574394 -0.11071695 Enter Image Size (Row, Column): 506 762 Enter Focal Length in mm: 29.4711992 Enter Camera Center (Xc, Yc, Zc): 3.451904 3.258335 1.254338 Enter pixel size in mm: 0.01838 Enter Rotation Angle w: -72.2993175 Enter Rotation Angle phi: 44.2841281 Enter Rotation Angle k: 166.5327547 Enter Distortion Parameters (k0, k1, k2): 0.0002 -0.00012443 0.00000011

---

hs: 1603.4384766050055 vs: 1603.4384766050055 hc: 375.79086289445047 vc: 259.0237731229597 C: [3.451904, 3.258335, 1.254338] A: [-0.698217 -0.6819946 -0.21766119] H: [-1378.70002113 894.469724 -106.50767804] V: [ 86.47420373 49.07120279 -1621.17935234] O: [-0.698217 -0.6819946 -0.21766119] R: [ 0.0002 -0.10807387 0.082982 ]

---

$ python3 get_photogrammetric_model.py

---

Note: Enter Vector Elements Row by Row with Space in between

Enter C Vector: 3.451904 3.258335 1.254338 Enter A Vector: -0.698217 -0.681994 -0.217661 Enter H Vector: -1378.872803 894.719666 -106.732689 Enter V Vector: 86.414558 49.038635 -1620.883789 Enter O Vector: -0.695858 -0.679843 -0.231508 Enter R Vector: 0.0002 -0.108075 0.086320 Enter pixel size in mm: 0.01838 Enter Image Size (Row, Column): 506 762 Enter hs: 1603.741455 Enter vs: 1603.1354 Enter hc: 375.790863 Enter vc: 259.023773

---

f: 29.476767942900004 Xc: 3.451904 Yc: 3.258335 Zc: 1.254338 x0: -0.09574393805999998 y0: -0.1107169477400001 Angle w (deg): -72.29916094406916 Angle phi (deg): 44.28412812851018 Angle k (deg): 166.5245817162046 k0: 0.0002 k1: -0.00012438428650870753 k2: 1.1433836611397755e-07

---

Reference
----------
* Di, Kaichang, and Rongxing Li. "CAHVOR camera model and its photogrammetric conversion for planetary applications." Journal of Geophysical Research: Planets 109.E4 (2004).