Most face-inpainting methods perform well in face repair. However, these methods can only complete a single face image per input. Although existing various image-inpainting methods can achieve pluralistic image inpainting, they typically produce faces with distorted structures or the same texture. To resolve these shortcomings and achieve high-quality diverse face inpainting, we propose PFTANet, a two-stage pluralistic face-inpainting network that transforms attribute information. In the first stage, the face-parsing network is fine-tuned to obtain semantic facial region information. In the second stage, a generator consisting of SNBlock, CF_ShiftBlocks, and CF_MergeBlock, which ensures that high-quality pluralistic face results are generated, is used. Specifically, CF_ShiftBlocks completes pluralistic face generation by transforming the attribute information from the conditional face extracted by the attribute extractor and ensuring the consistency of the attribute information between the conditional and generated faces. CF_MergeBlock ensures structural consistency between the masked and background regions of the generated face using facial region semantic information. A multi-patch discriminator is used to enhance facial detail generation. Experimental results for the CelebA and CelebA-HQ datasets indicated that PFTANet achieved pluralistic and visually realistic face inpainting.

Abstract Radiation therapy is the standard treatment for early stage Nasopharyngeal cancer (NPC). Thus, accurate delineation of target volumes at risk in NPC is important. While manual delineation is time‐consuming and labour‐intensive process and also leads to significant inter‐ and intra‐practitioner variability. Thus, computer‐aided segmentation algorithm is required. However, segmentation task is not trivial due to large variations (e.g., shape and size) of nasopharynx structure across subjects. Moreover, extreme foreground and background class imbalance in NPC segmentation remains challenge. In this paper, we propose a threedimensional densely connected convolutional neural network with multi‐scale feature pyramids for NPC segmentation. We adapt the densely connected convolutional block into a new structure via adding feature pyramids. The concatenated pyramid feature carries multi‐scale and hierarchical semantic information which is effective for segmenting different size of tumors and perceiving hierarchical context information. To address the foreground and background imbalance problem, we propose an enhanced version of focal loss. It prevents the large number of negative voxels far from boundaries from overwhelming the segmentation algorithm. We validated the proposed method on 120 clinical subjects. Experimental results demonstrate that our approach out‐performed state‐of‐the‐art methods and human experts.

This paper focuses on the semi-supervised object detection (SSOD) which makes good use of unlabeled data to boost performance. We face the following obstacles when adapting the knowledge distillation (KD) framework in SSOD. (1) The teacher model serves a dual role as a teacher and a student, such that the teacher predictions on unlabeled images may limit the upper bound of the student. (2) The data imbalance issue caused by the large quantity of consistent predictions between the teacher and student hinders an efficient knowledge transfer between them. To mitigate these issues, we propose a novel SSOD model called Temporal Self-Ensembling Teacher (TSET). Our teacher model ensembles its temporal predictions for unlabeled images under stochastic perturbations. Then, our teacher model ensembles its model weights with those of the student model by an exponential moving average. These ensembling strategies ensure data and model diversity, and lead to better teacher predictions for unlabeled images. In addition, we adapt the focal loss to formulate the consistency loss for handling the data imbalance issue. Together with a thresholding method, the focal loss automatically reweights the inconsistent predictions, which preserves the knowledge for difficult objects to detect in the unlabeled images. The mAP of our model reaches 80.73% and 40.52% on the VOC2007 test set and the COCO2014minival5kset, respectively, and outperforms a strong fully supervised detector by 2.37% and 1.49%, respectively. Furthermore, the mAP of our model (80.73%) sets a new state-of-the-art performance in SSOD on the VOC2007 test set.

For dilated cardiomyopathy (DCM) patients, immediate emergency diagnosis and treatment are critical for life saving and later recovery.T1 mapping is a non-invasive and effective diagnostic imaging approach to detect DCM.However, it is a demanding and time-consuming approach.In this paper, we propose an attention-based network structure, which can automatically identify DCM patients in a speedy manner to prioritize their treatment.In the proposed method, we adopt attention modules to generate attention-aware features.Inside each attention module, a bottom-up top-down feed-forward structure is used to unfold the feed-forward and feed-back attention processes into a single feed-forward process.It allows the network to focus more on determining useful information about the current output that is significant in the input data.Moreover, inspired by the residual network idea, we make full use of the characteristics of the original data.Combined residual block, we design down-residual modules for classification tasks.It consists of seven convolution layers and three layers of residual blocks.Our network achieves the most advanced recognition performance on cardiac datasets.We evaluated our approach on CMR(cardiac magnetic resonance) T1 mapping images with lower PSNR(peak signal to noise ratio), and the results demonstrate that our architecture outperforms previous approaches.

This paper presents a novel method for respiratory motion compensated reconstruction for cone beam computed tomography (CBCT). The reconstruction is based on a time sequence of motion vector fields, which is generated by a dynamic geometrical object shape model. The dynamic model is extracted from the 2D projection images of the CBCT. The process of the motion extraction is converted into an optimal 3D multiple interrelated surface detection problem, which can be solved by computing a maximum flow in a 4D directed graph. The method was tested on 12 mega-voltage (MV) CBCT scans from three patients. Two sets of motion-artifact-free 3D volumes, full exhale (FE) and full inhale (FI) phases, were reconstructed for each daily scan. The reconstruction was compared with three other motion-compensated approaches based on quantification accuracy of motion and size. Contrast-to-noise ratio (CNR) was also quantified for image quality. The proposed approach has the best overall performance, with a relative tumor volume quantification error of 3.39 ± 3.64% and 8.57 ± 8.31% for FE and FI phases, respectively. The CNR near the tumor area is 3.85 ± 0.42 (FE) and 3.58 ± 3.33 (FI). These results show the clinical feasibility to use the proposed method to reconstruct motion-artifact-free MVCBCT volumes.

Imaging techniques for measuring lung ventilation are essential tools to study lung tissue response to radiation therapy. Most of the existing CT and image registration based ventilation measurement methods use two extreme phases (end expiration and end inspiration) while ignoring the important ventilation variation within the respiratory cycle. In this paper, we present a new instantaneous ventilation measurement scheme using multiple 4DCT phase images and regularized 3D image registration, which aims at measuring the regional ventilation within the respiratory cycle. The ventilation is measured using the Jacobian (a function of local partial derivatives) of the registration displacement field. For all four animals, 39% of the total lung volume reaches maximum ventilation at T2(50% inspiration phase) during inspiration and the 75% of the total lung volume reaches maximum ventilation at T5(75% expiration phase) during expiration. The registration accuracy assessed by 200 semi automatically matched landmarks in all phases and animals show landmark error on the order of 1 mm after registration.

EMPIRE10 (Evaluation of Methods for Pulmonary Image REgistration 2010) is a public platform for fair and meaningful comparison of registration algorithms which are applied to a database of intrapatient thoracic CT image pairs. Evaluation of nonrigid registration techniques is a nontrivial task. This is compounded by the fact that researchers typically test only on their own data, which varies widely. For this reason, reliable assessment and comparison of different registration algorithms has been virtually impossible in the past. In this work we present the results of the launch phase of EMPIRE10, which comprised the comprehensive evaluation and comparison of 20 individual algorithms from leading academic and industrial research groups. All algorithms are applied to the same set of 30 thoracic CT pairs. Algorithm settings and parameters are chosen by researchers expert in the configuration of their own method and the evaluation is independent, using the same criteria for all participants. All results are published on the EMPIRE10 website (http://empire10.isi.uu.nl). The challenge remains ongoing and open to new participants. Full results from 24 algorithms have been published at the time of writing. This paper details the organization of the challenge, the data and evaluation methods and the outcome of the initial launch with 20 algorithms. The gain in knowledge and future work are discussed.