HzProc

Created by Hang Zhang

HzProc is a fast data augmentation toolbox supporting affine transformation with GPU backend. (PyTorch version is also provide.) The name of “HzProc” means high speed image processing, where “Hz” (hertz)
is the unit of frequency and “Proc” is abbreviation of processing. HZ is also the initial of the author.

It contains the functions within the following subcategories:

Quick Start Example

• Online
  • Crop and Flip
  • Affine Transformation
  • Get Affine Matrix
• Offline
  • Remap
  • Get Lookup Table
  • Combine Transforms

Install

This package relies on torch7 and
cutorch. Please note the package
also relies on a NVIDIA GPU compitable with CUDA 6.5 or higher version.

On Linux

luarocks install https://raw.githubusercontent.com/zhanghang1989/hzproc/master/hzproc-scm-1.rockspec

On OSX

CC=clang CXX=clang++ luarocks install https://raw.githubusercontent.com/zhanghang1989/hzproc/master/hzproc-scm-1.rockspec

Quick Demo

Demo The demo script relies on qtlua and
image package to load and display
the images. The test script is also a good usage example.
The documentations can be found in the link.

git clone https://github.com/zhanghang1989/hzproc
cd hzproc
qlua test/demo.lua

Fast Examples

• online example:

  function RandomCrop(size, pad)
  return function(input)
        -- avoid unnecessary opterations
    local w, h = input:size(3), input:size(2)
    if w == size and h == size then
      return input
    end
    local x1, y1 = torch.random(0, w + 2*pad - size), 
                                    torch.random(0, h + 2*pad - size)
    local out = hzproc.Crop.Pad(input, x1, y1, size, size, pad)
    assert(out:size(2) == size and out:size(3) == size, 'wrong crop size')
    return out
  end
  end

• offline example:
  ```lua
  function Resize(inw, inh, ow, oh)
  — generating the lookup map only once during init
  local map = hzproc.Table.Resize(inw, inh, ow, oh)
  return function(input)

    -- avoid unnecessary opterations
  local w, h = input:size(3), input:size(2)

  if (w == ow and h == oh) then

  return input

  end

    -- mapping
    return hzproc.Remap.Bilinear(input, map)

  end
  end

```