GstCUDA - Example - opencvwarp

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Introduction

The opencvwarp element will modify an image given a 3x3 transformation matrix. If the demo property of the element is enabled, it will apply a transformation that involves a rotation of the image in a 3D space and then a projection back to the image plane like this:

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Figure 1. Opencvwarp demo transformation

Element properties

• name
  

Name of the object.
Type: String
Flags: readable, writable
Default: "opencvwarp0"

• parent
  

The parent of the object.
Type: GstObject
Flags: readable, writable

• qos
  

Handle Quality-of-Service events.
Type: Boolean
Flags: readable, writable
Default: false

• m00
  

Coefficient 0,0 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 1

• m01
  

Coefficient 0,1 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m02
  

Coefficient 0,2 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m10
  

Coefficient 1,0 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m11
  

Coefficient 1,1 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 1

• m12
  

Coefficient 1,2 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m20
  

Coefficient 2,0 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m21
  

Coefficient 2,1 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 0

• m22
  

Coefficient 2,2 (row, column) of the transform matrix.
Type: Double
Range: -1,797693e+308 - 1,797693e+308 Flags: readable, writable
Default: 1

• demo
  

Put the element in demo mode to showcase it's capabilities. In this mode the incoming image will be rotated in the 3D space and projected back to the image plane. Will override the transformation matrix.
Type: Boolean
Flags: readable, writable
Default: false

Examples

The following two examples will provide an introduction to the element and its capabilities. Both examples were tested on Nvidia Jetson TX1 and TX2 connected to a display via HDMI and using a webcam as input video source.

Demo example

This example is meant to show the element capabilities. The image will be rotated in three-dimensional space and projected back to the image plane.

By running the following pipeline:

gst-launch-1.0 v4l2src ! nvvidconv ! opencvwarp demo=true ! queue ! nvvidconv ! autovideosink

you should obtain the result shown in Figure 1.