https://github.com/gfacciol/pypatchmatch

A simple C++ implementation of the PatchMatch Algorithm [Barnes, 2009] with its Cython and Matlab wrappers
https://github.com/gfacciol/pypatchmatch

Last synced: 18 days ago
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A simple C++ implementation of the PatchMatch Algorithm [Barnes, 2009] with its Cython and Matlab wrappers

• Host: GitHub
• URL: https://github.com/gfacciol/pypatchmatch
• Owner: gfacciol
• License: bsd-2-clause
• Created: 2016-07-10T22:37:38.000Z (over 8 years ago)
• Default Branch: master
• Last Pushed: 2021-06-26T22:51:59.000Z (over 3 years ago)
• Last Synced: 2024-10-10T19:11:45.221Z (about 1 month ago)
• Language: C
• Homepage:
• Size: 338 KB
• Stars: 10
• Watchers: 3
• Forks: 9
• Open Issues: 1
• Metadata Files:
  • Readme: readme.txt
  • License: LICENSE

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README

        
A simple implementation of the PatchMatch Algorithm [Barnes, 2009],

with its Cython and Matlab wrapper by Gabriele Facciolo ([email protected])

PatchMatch is a randomized matching algorithm that allows to efficiently 

compute the correspondence (offset) map between two images. 

Build standalone program

========================

> mkdir build; cd build

> cmake ../; make

quick test

> ./patchmatch -t SSD -i 10 -w 7 ../{b,a}.png -R 26 offset.tif cost.tif backproj.png

Usage: ./patchmatch [-i iter(5)] [-w patch_size(7)] [-d init_off]

        [-t patchdist={SSD(default)|SAD|ZSSD|ZSAD|NCC}]

        [-r min_off(0)] [-R max_off(10)] u v offset [cost [backflow]]

The offset.tif output image will have two channels with float values,

for the column and row offset, respectively, from the left to the

right image.

This algorithm does not compute a subpixel offset or perform a

left-right consistency check.

Options:

-i iter

   Number of iterations. A larger offset may need more iterations to

   converge.

-w patch_size

    Use a patch (block) of this size around each pixel in the left

    image to match to the right image.

-t patchdist

    The distance function to use to measure the similarity between

    patches in the two images.

-R max_off

    Search for the offset between -max_off and max_off. The algorithm

    should not be given a value for this much larger than what is

    expected, as that may result in incorrect results in some places.

-r min_off

    Do not search for offsets between -min_off and min_off.

   

-h 

    Search only horizontal offsets, by default offsets are 2D.   

build cython module

===================

> python setup.py build

copy module to the place where test-patchmatch.py is

> ln -s build//patchmatch.so patchmatch.so

run test program

> python test-patchmatch.py

call patchmatch from python

===========================

the patchmatch interface inside patchmatch.pyx is

   def pm(np.ndarray[np.float32_t, ndim=3, mode='c'] u1,

          np.ndarray[np.float32_t, ndim=3, mode='c'] u2,

          np.ndarray[np.float32_t, ndim=3, mode='c'] nnf,

          np.ndarray[np.float32_t, ndim=2, mode='c'] cost,

          patchsz,         # patch size

          minoff,          # minimum offset

          maxoff,          # maximum offset

          n_iter=5,        # iterations

          n_rand=5,        # random trials per iteration

          method='SAD'):   # patch distance: SAD, SSD, ZSSD, ZSAD, NCC

      '''

      returns the NNF field and the COST

      '''

usage example

        import patchmatch as pm

        # read images img0,img1 as np.arrays

        ...

        # parameters

        patchSize = 7

        maxoff, minoff = 100, 30

        

        # fix input types

        img0 = img0.astype(numpy.float32)

        img1 = img1.astype(numpy.float32)

        # create output arrays (with the correct type)

        sz   = img0.shape;

        nnf  = numpy.ndarray((sz[0],sz[1],2)).astype(numpy.float32);

        cost = numpy.ndarray((sz[0],sz[1]  )).astype(numpy.float32);

        # call patchmatch

        pm.pm(img0, img1, nnf, cost, patchSize, minoff, maxoff)

        # here are the offsets

        dx = nnf[:,:,0] 

        dy = nnf[:,:,1] 

build matlab mex

================

> compileMex

run test

> a = double(imread('a.png'));

> b = double(imread('b.png'));

> [n,c] = patchmatchMex(a,b);