If I provide you a face image of mine (without telling you the actual age when I took the picture) and a large amount of face images that I crawled (containing labeled faces of different ages but not necessarily paired), can you show me what I would look like when I am 80 or what I was like when I was 5?" The answer is probably a "No."Most existing face aging works attempt to learn the transformation between age groups and thus would require the paired samples as well as the labeled query image. In this paper, we look at the problem from a generative modeling perspective such that no paired samples is required. In addition, given an unlabeled image, the generative model can directly produce the image with desired age attribute. We propose a conditional adversarial autoencoder (CAAE) that learns a face manifold, traversing on which smooth age progression and regression can be realized simultaneously. In CAAE, the face is first mapped to a latent vector through a convolutional encoder, and then the vector is projected to the face manifold conditional on age through a deconvolutional generator. The latent vector preserves personalized face features (i.e., personality) and the age condition controls progression vs. regression. Two adversarial networks are imposed on the encoder and generator, respectively, forcing to generate more photo-realistic faces. Experimental results demonstrate the appealing performance and flexibility of the proposed framework by comparing with the state-of-the-art and ground truth.

与传统的头像创建管道相反，这是一个昂贵的过程，现代生成方法直接从照片中学习数据分布，而艺术的状态现在可以产生高度的照片现实图像。尽管大量作品试图扩展无条件的生成模型并达到一定程度的可控性，但要确保多视图一致性，尤其是在大型姿势中，仍然具有挑战性。在这项工作中，我们提出了一个3D肖像生成网络，该网络可产生3D一致的肖像，同时根据有关姿势，身份，表达和照明的语义参数可控。生成网络使用神经场景表示在3D中建模肖像，其生成以支持明确控制的参数面模型为指导。尽管可以通过将图像与部分不同的属性进行对比，但可以进一步增强潜在的分离，但在非面积区域（例如，在动画表达式）时，仍然存在明显的不一致。我们通过提出一种体积混合策略来解决此问题，在该策略中，我们通过将动态和静态辐射场融合在一起，形成一个复合输出，并从共同学习的语义场中分割了两个部分。我们的方法在广泛的实验中优于先前的艺术，在自由视点中观看时，在自然照明中产生了逼真的肖像。所提出的方法还证明了真实图像以及室外卡通面孔的概括能力，在实际应用中显示出巨大的希望。其他视频结果和代码将在项目网页上提供。

最近关于多领域面部图像翻译的研究取得了令人印象深刻的结果。现有方法通常提供具有辅助分类器的鉴别器，以施加域转换。但是，这些方法忽略了关于域分布匹配的重要信息。为了解决这个问题，我们提出了一种与更自适应的鉴别器结构和匹配的发电机具有更自适应的鉴别器结构和匹配的发电机之间的开关生成的对抗网络（SwitchGan），以在多个域之间执行精密图像转换。提出了一种特征切换操作以在我们的条件模块中实现特征选择和融合。我们展示了我们模型的有效性。此外，我们还引入了发电机的新功能，该功能代表了属性强度控制，并在没有定制培训的情况下提取内容信息。在视觉上和定量地显示了Morph，RAFD和Celeba数据库的实验，表明我们扩展的SwitchGan（即，门控SwitchGan）可以实现比Stargan，Attgan和Staggan更好的翻译结果。使用培训的Reset-18模型实现的属性分类准确性和使用ImageNet预先预订的Inception-V3模型获得的FIC分数也定量展示了模型的卓越性能。

鉴于输入面部照片，漫画生成的目标是生产风格化，夸张的漫画，与照片共享与相同的身份。它需要同时传输和形状夸张，具有丰富的多样性，同时保留输入的身份。为了解决这一具有挑战性的问题，我们提出了一种名为Multi-Warping GaN（MW-GAN）的新型框架，包括风格网络和几何网络，旨在分别进行样式传输和几何夸张。我们通过双向设计弥合图像的风格和地标之间的差距，并通过双向设计来生成具有任意样式和几何夸张的漫画，可以通过潜在代码或给定的随机采样来指定漫画样本。此外，我们对图像空间和地标空间施加身份保持损失，导致产生漫画的质量的巨大改善。实验表明，由MW-GaN产生的漫画具有比现有方法更好的质量。

Many image-to-image translation problems are ambiguous, as a single input image may correspond to multiple possible outputs. In this work, we aim to model a distribution of possible outputs in a conditional generative modeling setting. The ambiguity of the mapping is distilled in a low-dimensional latent vector, which can be randomly sampled at test time. A generator learns to map the given input, combined with this latent code, to the output. We explicitly encourage the connection between output and the latent code to be invertible. This helps prevent a many-to-one mapping from the latent code to the output during training, also known as the problem of mode collapse, and produces more diverse results. We explore several variants of this approach by employing different training objectives, network architectures, and methods of injecting the latent code. Our proposed method encourages bijective consistency between the latent encoding and output modes. We present a systematic comparison of our method and other variants on both perceptual realism and diversity.

本文的目标是对面部素描合成（FSS）问题进行全面的研究。然而，由于获得了手绘草图数据集的高成本，因此缺乏完整的基准，用于评估过去十年的FSS算法的开发。因此，我们首先向FSS引入高质量的数据集，名为FS2K，其中包括2,104个图像素描对，跨越三种类型的草图样式，图像背景，照明条件，肤色和面部属性。 FS2K与以前的FSS数据集不同于难度，多样性和可扩展性，因此应促进FSS研究的进展。其次，我们通过调查139种古典方法，包括34个手工特征的面部素描合成方法，37个一般的神经式传输方法，43个深映像到图像翻译方法，以及35个图像 - 素描方法。此外，我们详细说明了现有的19个尖端模型的综合实验。第三，我们为FSS提供了一个简单的基准，名为FSGAN。只有两个直截了当的组件，即面部感知屏蔽和风格矢量扩展，FSGAN将超越所提出的FS2K数据集的所有先前最先进模型的性能，通过大边距。最后，我们在过去几年中汲取的经验教训，并指出了几个未解决的挑战。我们的开源代码可在https://github.com/dengpingfan/fsgan中获得。

The primary aim of single-image super-resolution is to construct a high-resolution (HR) image from a corresponding low-resolution (LR) input. In previous approaches, which have generally been supervised, the training objective typically measures a pixel-wise average distance between the super-resolved (SR) and HR images. Optimizing such metrics often leads to blurring, especially in high variance (detailed) regions. We propose an alternative formulation of the super-resolution problem based on creating realistic SR images that downscale correctly. We present a novel super-resolution algorithm addressing this problem, PULSE (Photo Upsampling via Latent Space Exploration), which generates high-resolution, realistic images at resolutions previously unseen in the literature. It accomplishes this in an entirely self-supervised fashion and is not confined to a specific degradation operator used during training, unlike previous methods (which require training on databases of LR-HR image pairs for supervised learning). Instead of starting with the LR image and slowly adding detail, PULSE traverses the high-resolution natural image manifold, searching for images that downscale to the original LR image. This is formalized through the "downscaling loss," which guides exploration through the latent space of a generative model. By leveraging properties of high-dimensional Gaussians, we restrict the search space to guarantee that our outputs are realistic. PULSE thereby generates super-resolved images that both are realistic and downscale correctly. We show extensive experimental results demonstrating the efficacy of our approach in the domain of face super-resolution (also known as face hallucination). We also present a discussion of the limitations and biases of the method as currently implemented with an accompanying model card with relevant metrics. Our method outperforms state-of-the-art methods in perceptual quality at higher resolutions and scale factors than previously pos-sible.

随着脑成像技术和机器学习工具的出现，很多努力都致力于构建计算模型来捕获人脑中的视觉信息的编码。最具挑战性的大脑解码任务之一是通过功能磁共振成像（FMRI）测量的脑活动的感知自然图像的精确重建。在这项工作中，我们调查了来自FMRI的自然图像重建的最新学习方法。我们在架构设计，基准数据集和评估指标方面检查这些方法，并在标准化评估指标上呈现公平的性能评估。最后，我们讨论了现有研究的优势和局限，并提出了潜在的未来方向。

Facial attribute editing aims to manipulate single or multiple attributes of a face image, i.e., to generate a new face with desired attributes while preserving other details. Recently, generative adversarial net (GAN) and encoder-decoder architecture are usually incorporated to handle this task with promising results. Based on the encoder-decoder architecture, facial attribute editing is achieved by decoding the latent representation of the given face conditioned on the desired attributes. Some existing methods attempt to establish an attributeindependent latent representation for further attribute editing. However, such attribute-independent constraint on the latent representation is excessive because it restricts the capacity of the latent representation and may result in information loss, leading to over-smooth and distorted generation. Instead of imposing constraints on the latent representation, in this work we apply an attribute classification constraint to the generated image to just guarantee the correct change of desired attributes, i.e., to "change what you want". Meanwhile, the reconstruction learning is introduced to preserve attribute-excluding details, in other words, to "only change what you want". Besides, the adversarial learning is employed for visually realistic editing. These three components cooperate with each other forming an effective framework for high quality facial attribute editing, referred as AttGAN. Furthermore, our method is also directly applicable for attribute intensity control and can be naturally extended for attribute style manipulation. Experiments on CelebA dataset show that our method outperforms the state-of-the-arts on realistic attribute editing with facial details well preserved.

Realistic image manipulation is challenging because it requires modifying the image appearance in a user-controlled way, while preserving the realism of the result. Unless the user has considerable artistic skill, it is easy to "fall off" the manifold of natural images while editing. In this paper, we propose to learn the natural image manifold directly from data using a generative adversarial neural network. We then define a class of image editing operations, and constrain their output to lie on that learned manifold at all times. The model automatically adjusts the output keeping all edits as realistic as possible. All our manipulations are expressed in terms of constrained optimization and are applied in near-real time. We evaluate our algorithm on the task of realistic photo manipulation of shape and color. The presented method can further be used for changing one image to look like the other, as well as generating novel imagery from scratch based on user's scribbles 1 .

深度神经网络在人类分析中已经普遍存在，增强了应用的性能，例如生物识别识别，动作识别以及人重新识别。但是，此类网络的性能通过可用的培训数据缩放。在人类分析中，对大规模数据集的需求构成了严重的挑战，因为数据收集乏味，廉价，昂贵，并且必须遵守数据保护法。当前的研究研究了\ textit {合成数据}的生成，作为在现场收集真实数据的有效且具有隐私性的替代方案。这项调查介绍了基本定义和方法，在生成和采用合成数据进行人类分析时必不可少。我们进行了一项调查，总结了当前的最新方法以及使用合成数据的主要好处。我们还提供了公开可用的合成数据集和生成模型的概述。最后，我们讨论了该领域的局限性以及开放研究问题。这项调查旨在为人类分析领域的研究人员和从业人员提供。

Although Generative Adversarial Networks (GANs) have made significant progress in face synthesis, there lacks enough understanding of what GANs have learned in the latent representation to map a random code to a photo-realistic image. In this work, we propose a framework called InterFaceGAN to interpret the disentangled face representation learned by the state-of-the-art GAN models and study the properties of the facial semantics encoded in the latent space. We first find that GANs learn various semantics in some linear subspaces of the latent space. After identifying these subspaces, we can realistically manipulate the corresponding facial attributes without retraining the model. We then conduct a detailed study on the correlation between different semantics and manage to better disentangle them via subspace projection, resulting in more precise control of the attribute manipulation. Besides manipulating the gender, age, expression, and presence of eyeglasses, we can even alter the face pose and fix the artifacts accidentally made by GANs. Furthermore, we perform an in-depth face identity analysis and a layer-wise analysis to evaluate the editing results quantitatively. Finally, we apply our approach to real face editing by employing GAN inversion approaches and explicitly training feed-forward models based on the synthetic data established by InterFaceGAN. Extensive experimental results suggest that learning to synthesize faces spontaneously brings a disentangled and controllable face representation.

心血管疾病是全球死亡的主要原因，是一种与年龄有关的疾病。了解衰老期间心脏的形态和功能变化是一个关键的科学问题，其答案将有助于我们定义心血管疾病的重要危险因素并监测疾病进展。在这项工作中，我们提出了一种新型的条件生成模型，以描述衰老过程中心脏3D解剖学的变化。提出的模型是灵活的，可以将多个临床因素（例如年龄，性别）整合到生成过程中。我们在心脏解剖学的大规模横截面数据集上训练该模型，并在横截面和纵向数据集上进行评估。该模型在预测衰老心脏的纵向演化和对其数据分布进行建模方面表现出了出色的表现。

Generative models, as an important family of statistical modeling, target learning the observed data distribution via generating new instances. Along with the rise of neural networks, deep generative models, such as variational autoencoders (VAEs) and generative adversarial network (GANs), have made tremendous progress in 2D image synthesis. Recently, researchers switch their attentions from the 2D space to the 3D space considering that 3D data better aligns with our physical world and hence enjoys great potential in practice. However, unlike a 2D image, which owns an efficient representation (i.e., pixel grid) by nature, representing 3D data could face far more challenges. Concretely, we would expect an ideal 3D representation to be capable enough to model shapes and appearances in details, and to be highly efficient so as to model high-resolution data with fast speed and low memory cost. However, existing 3D representations, such as point clouds, meshes, and recent neural fields, usually fail to meet the above requirements simultaneously. In this survey, we make a thorough review of the development of 3D generation, including 3D shape generation and 3D-aware image synthesis, from the perspectives of both algorithms and more importantly representations. We hope that our discussion could help the community track the evolution of this field and further spark some innovative ideas to advance this challenging task.

由于简单但有效的训练机制和出色的图像产生质量，生成的对抗网络（GAN）引起了极大的关注。具有生成照片现实的高分辨率（例如$ 1024 \ times1024 $）的能力，最近的GAN模型已大大缩小了生成的图像与真实图像之间的差距。因此，许多最近的作品表明，通过利用良好的潜在空间和博学的gan先验来利用预先训练的GAN模型的新兴兴趣。在本文中，我们简要回顾了从三个方面利用预先培训的大规模GAN模型的最新进展，即1）大规模生成对抗网络的培训，2）探索和理解预训练的GAN模型，以及预先培训的GAN模型，以及3）利用这些模型进行后续任务，例如图像恢复和编辑。有关相关方法和存储库的更多信息，请访问https://github.com/csmliu/pretretaining-gans。

Facial image manipulation has achieved great progress in recent years. However, previous methods either operate on a predefined set of face attributes or leave users little freedom to interactively manipulate images. To overcome these drawbacks, we propose a novel framework termed MaskGAN, enabling diverse and interactive face manipulation. Our key insight is that semantic masks serve as a suitable intermediate representation for flexible face manipulation with fidelity preservation. MaskGAN has two main components: 1) Dense Mapping Network (DMN) and 2) Editing Behavior Simulated Training (EBST). Specifically, DMN learns style mapping between a free-form user modified mask and a target image, enabling diverse generation results. EBST models the user editing behavior on the source mask, making the overall framework more robust to various manipulated inputs. Specifically, it introduces dual-editing consistency as the auxiliary supervision signal. To facilitate extensive studies, we construct a large-scale high-resolution face dataset with fine-grained mask annotations named CelebAMask-HQ. MaskGAN is comprehensively evaluated on two challenging tasks: attribute transfer and style copy, demonstrating superior performance over other state-of-the-art methods. The code, models, and dataset are available at https://github.com/switchablenorms/CelebAMask-HQ.

Image-generating machine learning models are typically trained with loss functions based on distance in the image space. This often leads to over-smoothed results. We propose a class of loss functions, which we call deep perceptual similarity metrics (DeePSiM), that mitigate this problem. Instead of computing distances in the image space, we compute distances between image features extracted by deep neural networks. This metric better reflects perceptually similarity of images and thus leads to better results. We show three applications: autoencoder training, a modification of a variational autoencoder, and inversion of deep convolutional networks. In all cases, the generated images look sharp and resemble natural images.

面部3D形态模型是无数应用程序的主要计算机视觉主题，并且在过去二十年中已得到高度优化。深层生成网络的巨大改进创造了改善此类模型的各种可能性，并引起了广泛的兴趣。此外，神经辐射领域的最新进展正在彻底改变已知场景的新颖视图综合。在这项工作中，我们提出了一个面部3D形态模型，该模型利用了上述两者，并且可以准确地对受试者的身份，姿势和表达进行建模，并以任意照明形式呈现。这是通过利用强大的基于风格的发电机来克服神经辐射场的两个主要弱点，即它们的刚度和渲染速度来实现的。我们介绍了一个基于样式的生成网络，该网络在一个通过中综合了全部，并且仅在神经辐射场的所需渲染样品中构成。我们创建了一个庞大的标记为面部渲染的合成数据集，并在这些数据上训练网络，以便它可以准确地建模并推广到面部身份，姿势和外观。最后，我们表明该模型可以准确地适合“野外”的任意姿势和照明的面部图像，提取面部特征，并用于在可控条件下重新呈现面部。

Generative adversarial networks (GANs) provide a way to learn deep representations without extensively annotated training data. They achieve this through deriving backpropagation signals through a competitive process involving a pair of networks. The representations that can be learned by GANs may be used in a variety of applications, including image synthesis, semantic image editing, style transfer, image super-resolution and classification. The aim of this review paper is to provide an overview of GANs for the signal processing community, drawing on familiar analogies and concepts where possible. In addition to identifying different methods for training and constructing GANs, we also point to remaining challenges in their theory and application.