crf.py

# Authors: Wouter Van Gansbeke & Simon Vandenhende
# Licensed under the CC BY-NC 4.0 license (https://creativecommons.org/licenses/by-nc/4.0/)

import numpy as np
import pydensecrf.densecrf as dcrf
import pydensecrf.utils as utils
import torch
import torch.nn.functional as F
import torchvision.transforms.functional as VF

POS_W = 3
POS_XY_STD = 1
Bi_W = 4
Bi_XY_STD = 67
Bi_RGB_STD = 3
BGR_MEAN = np.array([104.008, 116.669, 122.675])


def rgb_dense_crf(image, output_probs, max_iter=10):
    image = np.ascontiguousarray(image)

    c = output_probs.shape[0]
    h = output_probs.shape[1]
    w = output_probs.shape[2]

    U = utils.unary_from_softmax(output_probs)
    U = np.ascontiguousarray(U)

    d = dcrf.DenseCRF2D(w, h, c)
    d.setUnaryEnergy(U)
    d.addPairwiseGaussian(sxy=POS_XY_STD, compat=POS_W)
    d.addPairwiseBilateral(sxy=Bi_XY_STD, srgb=Bi_RGB_STD, rgbim=image, compat=Bi_W)

    Q = d.inference(max_iter)
    Q = np.array(Q).reshape((c, h, w))

    return Q