提問-MultiCol-SLAM魚眼相機的相機模型

%YAML:1.0

# Camera Parameters. Adjust them!
# Camera calibration parameters camera back
Camera.Iw: 754
Camera.Ih: 480

# hyperparameters
Camera.nrpol: 5
Camera.nrinvpol: 12

# forward polynomial f(\rho)
Camera.a0: -209.200757992065
Camera.a1: 0.0 
Camera.a2: 0.00213741670953883
Camera.a3: -4.2203617319086e-06
Camera.a4: 1.77146086919594e-08

# backward polynomial rho(\theta)
Camera.pol0: 293.667187375663
Camera.pol1: 149.982043337335
Camera.pol2: -10.448650568161
Camera.pol3: 28.2295300683376
Camera.pol4: 7.13365723186292
Camera.pol5: 0.056303218962532
Camera.pol6: 10.4144677485333
Camera.pol7: 0.166354960773665
Camera.pol8: -5.86858687381081
Camera.pol9: 1.18165998645705
Camera.pol10: 3.1108311354746
Camera.pol11: 0.810799620714366

# affine matrix
Camera.c: 0.999626131079017
Camera.d: -0.0034775192597376
Camera.e: 0.00385134991673147

# principal point
Camera.u0: 392.219508388648
Camera.v0: 243.494438476351

# create a mirror mask for fisheye cameras
Camera.mirrorMask: 1

以上是multicol-SLAM的相機內參，forward polynomial f(\rho) 和backward polynomial rho(\theta) 分別代表的物理意義是什麼？以及仿射變換矩陣affine matrix在這裏的作用是什麼？

對於同樣具有魚眼相機的openvslam系統，其魚眼相機的配置文件：

Camera.name: "TUM VI monocular"
Camera.setup: "monocular"
Camera.model: "fisheye"

Camera.fx: 190.97847715128717
Camera.fy: 190.9733070521226
Camera.cx: 254.93170605935475
Camera.cy: 256.8974428996504

Camera.k1: 0.0034823894022493434
Camera.k2: 0.0007150348452162257
Camera.k3: -0.0020532361418706202
Camera.k4: 0.00020293673591811182

Camera.fps: 20
Camera.cols: 512
Camera.rows: 512

Camera.color_order: "Gray"

參數就非常的簡潔，且很明瞭，k1-k4代表相機的徑向畸變參數（無切向畸變），那麼對於multiCol-SLAM，他的參數我就不那麼懂了，尤其是

Camera.a0: -209.200757992065
Camera.a1: 0.0 
Camera.a2: 0.00213741670953883
Camera.a3: -4.2203617319086e-06
Camera.a4: 1.77146086919594e-08

Camera.pol0: 293.667187375663
Camera.pol1: 149.982043337335
Camera.pol2: -10.448650568161
Camera.pol3: 28.2295300683376
Camera.pol4: 7.13365723186292
Camera.pol5: 0.056303218962532
Camera.pol6: 10.4144677485333
Camera.pol7: 0.166354960773665
Camera.pol8: -5.86858687381081
Camera.pol9: 1.18165998645705
Camera.pol10: 3.1108311354746
Camera.pol11: 0.810799620714366

分別代表的是什麼？希望得到大神的解答，不勝感激。