Image Flip

Overview

The image flip algorithm writes to the output image a mirrored version of the input. It supports mirroring along horizontal, vertical and both axis simultaneously. The latter is a useful and fast way to rotate the image 180 degrees.

Input	VPI_FLIP_HORIZ
VPI_FLIP_VERT	VPI_FLIP_BOTH

Implementation

The image flip works by swapping the pixels across the x-axis, y-axis or across both axes depending on how the user wants it.

• VPI_FLIP_HORIZ - Flips the image horizontally.
• VPI_FLIP_VERT - Flips the image vertically.
• VPI_FLIP_BOTH - Flips the image both horizontally and vertically.

C API functions

For list of limitations, constraints and backends that implements the algorithm, consult reference documentation of the following functions:

Function	Description
vpiSubmitImageFlip	Flips a 2D image either horizontally, vertically or both.

Usage

Language: C/C++ Python

1. Import VPI module

   import vpi

2. Run image flip on input image using the CUDA backend. It's using flip mode BOTH. Input and output are VPI images.

   with vpi.Backend.CUDA:
       output = input.image_flip(vpi.Flip.BOTH)

1. Initialization phase
   1. Include the header that defines the Image flip function.

      #include <vpi/algo/ImageFlip.h>

   2. Define the input image.

          VPIImage input = /*...*/;

   3. Create the output image. It gets its dimensions and format from the input image.

          int32_t w, h;
          vpiImageGetSize(input, &w, &h);
       
          VPIImageFormat type;
          vpiImageGetFormat(input, &type);
       
          VPIImage output;
          vpiImageCreate(w, h, type, 0, &output);

   4. Create the stream where the algorithm will be submitted for execution.

          VPIStream stream;
          vpiStreamCreate(0, &stream);

2. Processing phase
   1. Submit the algorithm to the stream using the CPU backend, along with all parameters.

          vpiSubmitImageFlip(stream, VPI_BACKEND_CPU, input, output, flipMode);

   2. Optionally, wait until the processing is done.

          vpiStreamSync(stream);

3. Cleanup phase
   1. Free resources held by the stream and the input and output images.

          vpiStreamDestroy(stream);
          vpiImageDestroy(input);
          vpiImageDestroy(output);

For more information, see Image Flip in the "C API Reference" section of VPI - Vision Programming Interface.

Performance

For information on how to use the performance table below, see Algorithm Performance Tables.
Before comparing measurements, consult Comparing Algorithm Elapsed Times.
For further information on how performance was benchmarked, see Performance Benchmark.

clear filters Device: Jetson AGX Xavier Jetson AGX Orin  -  Streams: 1 2 4 8