NVIDIA VPI GStreamer Plug-in - Examples - Undistort

GstVPI
GstVPI Basics
Getting Started
Evaluating GstVPI Getting the Code Building the Plugin
Examples
Gaussian Filter Undistort Harris Keypoints Detector KLT Tracker Perspective Warp Overlay Videoconvert Videoscale Convolution Separable Convolution
Performance
Nano TX1 TX2 Xavier
Contact Us

Introduction

The vpiundistort element applies the Lens Distortion Correction algorithm from the NVIDIA VPI library to a video stream. In order to use this algorithm you must provide the camera distortion parameters. See the next section to learn how to obtain them.

Element properties

• backend
  

Backend to use to execute VPI algorithms. Available options:

cpu: CPU backend

cuda: CUDA backend

pva: PVA backend (Xavier only)

vic: VIC backend

Flags: readable, writable
Default: "cuda"

• extrinsinc
  

3x4 matrix resulting of concatenation of 3x3 rotation matrix with 3x1 vector containing the position of the origin world coordinate system expressed in coordinates of camera-centered system.
Type: GstValueArray of GValues of type GstValueArray
Flags: readable, writable
Default: <<1.0,0.0,0.0,0.0>,<0.0,1.0,0.0,0.0>,<0.0,0.0,1.0,0.0>>

• intrinsic
  

2x3 matrix with the parameters: [[fx,s,cx],[0,fy,cy]] where:
- fx, fy: focal length in pixels in x and y direction
- s: skew
- cx, cy: the principal point in x and y direction
If not provided, a default calibration matrix will be created.
Type: GstValueArray of GValues of type GstValueArray
Flags: readable, writable
Default: <<f, 0.0, width/2>,<0.0, f, height/2>>. Where [math]\displaystyle{ f = 7.5 * width / 22.2 }[/math]

• interpolator
  

Interpolation method to be used. Available options:

nearest: Nearest neighbor interpolation

linear: Fast linear interpolation

catmull: Fast Catmull-Rom cubic interpolation

Flags: readable, writable
Default: "catmull"

• model
  

Type of distortion model to use. Available options:

fisheye: Fisheye distortion model

polynomial: Polynomial (Brown-Conrady) distortion model

Flags: readable, writable
Default: "fisheye"

• mapping
  

Type of fisheye lens mapping types (only for fisheye model). Available options:

equidistant: Specifies the equidistant fisheye mapping

equisolid: Specifies the equisolid fisheye mapping

ortographic: Specifies the ortographic fisheye mapping

stereographic: Specifies the stereographic fisheye mapping

Flags: readable, writable
Default: "equidistant"

• k1
  

Distortion coefficient 1 of the chosen distortion model (fisheye or polynomial).
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• k2
  

Distortion coefficient 2 of the chosen distortion model (fisheye or polynomial).
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• k3
  

Distortion coefficient 3 of the chosen distortion model (fisheye or polynomial).
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• k4
  

Distortion coefficient 4 of the chosen distortion model (fisheye or polynomial).
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• k5
  

Distortion coefficient 5. Only for polynomial model.
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• k6
  

Distortion coefficient 6. Only for polynomial model.
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• p1
  

Tangential distortion coefficient 1. Only for polynomial model.
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

• p2
  

Tangential distortion coefficient 2. Only for polynomial model.
Type: Double
Range: -1,797693e+308 - 1,797693e+308
Flags: readable, writable
Default: 0

Example

The following example pipes will help you correct the distortion from your camera lens. You may modify the properties values according to the information above. In these examples we provide some distortion coefficients and calibration matrices for the camera we used, however you should modify them according to your camera's parameters (see How to Obtain the Camera Calibration Parameters).

Polynomial Distortion

gst-launch-1.0 v4l2src ! nvvidconv ! 'video/x-raw(memory:NVMM)' ! nvvidconv ! vpiupload ! vpiundistort k1=0.52 k2=-0.02 p1=0 p2=0 k3=-0.001 k4=0.8 k5=0.05 k6=-0.008 model=polynomial intrinsic='<<305.95,0.0,654.03>,<0.0,305.23,415.65>>' ! vpidownload ! nvvidconv ! nvoverlaysink

Fisheye Distortion

gst-launch-1.0 v4l2src ! nvvidconv ! 'video/x-raw(memory:NVMM)' ! nvvidconv ! vpiupload ! vpiundistort k1=0.05 k2=0.01 k3=0 k4=0 model=fisheye intrinsic='<<305.95,0.0,654.03>,<0.0,305.23,415.65>>' mapping=equisolid ! vpidownload ! nvvidconv ! nvoverlaysink