def iterativeBackPropagation(hrImage, lrImages, lrMasks, transforms, H, itermax): y = [] for i in range(len(lrImages)): y.append( convert_image_to_vector(lrImages[i]) * convert_image_to_vector(lrMasks[i])) x = convert_image_to_vector(hrImage) outputImage = nibabel.Nifti1Image(hrImage.get_data(), hrImage.affine) hrMaskSum = np.zeros(hrImage.get_data().shape, dtype=np.float32) for i in range(len(lrImages)): tmp1 = apply_affine_itk_transform_on_image(input_image=lrMasks[i], transform=transforms[i][0], center=transforms[i][1], reference_image=hrImage, order=0) hrMaskSum += tmp1.get_data() index = np.nonzero(hrMaskSum) for j in range(itermax): #simulation and error computation hrError = np.zeros(hrImage.get_data().shape, dtype=np.float32) for i in range(len(lrImages)): lrError = convert_vector_to_image(H[i].dot(x) - y[i], lrImages[i]) tmp2 = apply_affine_itk_transform_on_image( input_image=lrError, transform=transforms[i][0], center=transforms[i][1], reference_image=hrImage, order=1) hrError += tmp2.get_data() hrError2 = np.zeros(hrImage.get_data().shape, dtype=np.float32) hrError2[index] = hrError[index] / hrMaskSum[index] #update hr image and x outputImage = nibabel.Nifti1Image(outputImage.get_data() - hrError2, hrImage.affine) nibabel.save(outputImage, 'ibp_iter' + str(j) + '.nii.gz') x = convert_image_to_vector(outputImage) return outputImage
def ibpComputeError(x, H, y, hrMaskSum, lrImages, transforms, interpOrder): hrError = np.zeros(hrMaskSum.get_data().shape, dtype=np.float32) #Loop over LR image to compute the sum of errors for i in range(len(lrImages)): lrError = convert_vector_to_image(H[i].dot(x) - y[i], lrImages[i]) tmp2 = apply_affine_itk_transform_on_image(input_image=lrError, transform=transforms[i][0], center=transforms[i][1], reference_image=hrMaskSum, order=interpOrder) hrError += tmp2.get_data() #Normalize the error image hrErrorNorm = np.zeros(hrMaskSum.get_data().shape, dtype=np.float32) index = np.nonzero(hrMaskSum.get_data()) hrErrorNorm[index] = hrError[index] / hrMaskSum.get_data()[index] return hrErrorNorm
def ibpComputeError(x, H, y, hrMaskSum, lrImages, transforms, interpOrder): hrError = np.zeros(hrMaskSum.get_data().shape, dtype=np.float32) # Loop over LR image to compute the sum of errors for i in range(len(lrImages)): lrError = convert_vector_to_image(H[i].dot(x) - y[i], lrImages[i]) tmp2 = apply_affine_itk_transform_on_image( input_image=lrError, transform=transforms[i][0], center=transforms[i][1], reference_image=hrMaskSum, order=interpOrder, ) hrError += tmp2.get_data() # Normalize the error image hrErrorNorm = np.zeros(hrMaskSum.get_data().shape, dtype=np.float32) index = np.nonzero(hrMaskSum.get_data()) hrErrorNorm[index] = hrError[index] / hrMaskSum.get_data()[index] return hrErrorNorm
for i in range(len(inputImages)): HList.append( compute_H(inputImages[i], initHRImage, inputTransforms[i], psfList[i], maskImages[i])) #Intensity correction To do #N4 on initHR #local correction #New init HR if args.bias == True: initHRImage_N4 = apply_N4_on_image(initHRImage, shrink_factor=1) xN4 = convert_image_to_vector(initHRImage_N4) hrN4Data = np.zeros(initHRImage.get_data().shape) for i in range(len(inputImages)): simu = convert_vector_to_image(HList[i].dot(xN4), inputImages[i]) im = gaussian_biais_correction(inputImages[i], simu, 5) warped = apply_affine_itk_transform_on_image( input_image=im, transform=inputTransforms[i][0], center=inputTransforms[i][1], reference_image=initHRImage, order=3) hrN4Data += (warped.get_data() / np.float32(len(inputImages))) initHRImage = nibabel.Nifti1Image(hrN4Data, initHRImage.affine) #Compute x x = convert_image_to_vector(initHRImage) maskX = convert_image_to_vector(maskHRImage) #Let mask the HR image
#Compute H HList = [] for i in range(len(inputImages)): HList.append( compute_H(inputImages[i], initHRImage, inputTransforms[i], psfList[i], maskImages[i]) ) #Intensity correction To do #N4 on initHR #local correction #New init HR if args.bias == True: initHRImage_N4 = apply_N4_on_image(initHRImage, shrink_factor=1) xN4 = convert_image_to_vector(initHRImage_N4) hrN4Data = np.zeros(initHRImage.get_data().shape) for i in range(len(inputImages)): simu = convert_vector_to_image(HList[i].dot(xN4),inputImages[i]) im = gaussian_biais_correction(inputImages[i],simu, 5) warped = apply_affine_itk_transform_on_image(input_image=im,transform=inputTransforms[i][0], center=inputTransforms[i][1], reference_image=initHRImage, order=3) hrN4Data += (warped.get_data() / np.float32(len(inputImages)) ) initHRImage = nibabel.Nifti1Image(hrN4Data, initHRImage.affine) #Compute x x = convert_image_to_vector(initHRImage) maskX = convert_image_to_vector(maskHRImage) #Let mask the HR image x = x*maskX #loop over LR images and stack y and masks maskList = [] yList = []
m = np.identity(4) c = np.array([0, 0, 0, 1]) inputTransform = (m, c) print('Creating mask image using the following padding value:' + str(args.padding)) data = np.zeros(HRimage.get_data().shape) data[HRimage.get_data() > args.padding] = 1 maskHRImage = nibabel.Nifti1Image(data, HRimage.affine) print('Percentage of HR masked values : %.2f ' % (np.size(np.nonzero( (data))) / (1.0 * np.size(data.shape)) * 100.0 / np.size(data))) data = np.zeros(LRimage.get_data().shape) data[LRimage.get_data() > args.padding] = 1 maskLRImage = nibabel.Nifti1Image(data, LRimage.affine) print('Percentage of LR masked values : %.2f ' % (np.size(np.nonzero( (data))) / (1.0 * np.size(data.shape)) * 100.0 / np.size(data))) HRSpacing = np.float32(np.array(HRimage.header['pixdim'][1:4])) LRSpacing = np.float32(np.array(LRimage.header['pixdim'][1:4])) psf = compute_psf(LRSpacing, HRSpacing, args.psf) H = compute_H(LRimage, HRimage, inputTransform, psf, maskLRImage) x = convert_image_to_vector(HRimage) maskX = convert_image_to_vector(maskHRImage) #Let mask the HR image x = x * maskX nibabel.save(convert_vector_to_image(H.dot(x), LRimage), args.output)
else: #no transform provided : use identity as transform and zero as center m = np.identity(4) c = np.array([0, 0, 0, 1]) inputTransform = (m,c) print('Creating mask image using the following padding value:'+str(args.padding)) data = np.zeros(HRimage.get_data().shape) data[HRimage.get_data() > args.padding] = 1 maskHRImage = nibabel.Nifti1Image(data, HRimage.affine) print('Percentage of HR masked values : %.2f '%( np.size(np.nonzero((data))) / (1.0*np.size(data.shape)) * 100.0 / np.size(data) ) ) data = np.zeros(LRimage.get_data().shape) data[LRimage.get_data() > args.padding] = 1 maskLRImage = nibabel.Nifti1Image(data, LRimage.affine) print('Percentage of LR masked values : %.2f '%( np.size(np.nonzero((data))) / (1.0*np.size(data.shape)) * 100.0 / np.size(data) ) ) HRSpacing = np.float32(np.array(HRimage.header['pixdim'][1:4])) LRSpacing = np.float32(np.array(LRimage.header['pixdim'][1:4])) psf = compute_psf(LRSpacing, HRSpacing, args.psf) H = compute_H(LRimage, HRimage, inputTransform, psf, maskLRImage) x = convert_image_to_vector(HRimage) maskX = convert_image_to_vector(maskHRImage) #Let mask the HR image x = x*maskX nibabel.save(convert_vector_to_image(H.dot(x),LRimage),args.output)
# Compute H HList = [] for i in range(len(inputImages)): HList.append(compute_H(inputImages[i], initHRImage, inputTransforms[i], psfList[i], maskImages[i])) # Intensity correction To do # N4 on initHR # local correction # New init HR if args.bias == True: initHRImage_N4 = apply_N4_on_image(initHRImage, shrink_factor=1) xN4 = convert_image_to_vector(initHRImage_N4) hrN4Data = np.zeros(initHRImage.get_data().shape) for i in range(len(inputImages)): simu = convert_vector_to_image(HList[i].dot(xN4), inputImages[i]) im = gaussian_biais_correction(inputImages[i], simu, 5) warped = apply_affine_itk_transform_on_image( input_image=im, transform=inputTransforms[i][0], center=inputTransforms[i][1], reference_image=initHRImage, order=3, ) hrN4Data += warped.get_data() / np.float32(len(inputImages)) initHRImage = nibabel.Nifti1Image(hrN4Data, initHRImage.affine) # Compute x x = convert_image_to_vector(initHRImage) maskX = convert_image_to_vector(maskHRImage)