In this paper, we develop a new optical interferometric telescope architecture based on compressive sensing (CS) theory. Traditional optical telescopes with large apertures must be large in size, heavy and have high-power consumption, which limits the development of space-based telescopes. A turning point has occurred in the advent of imaging technology that utilizes Fourier-domain interferometry. This technology can reduce the system size, weight and power consumption by an order of magnitude compared to traditional optical telescopes at the same resolution. CS theory demonstrates that incomplete and noisy Fourier measurements may suffice for the exact reconstruction of sparse or compressible signals. Our proposed architecture combines advantages from the two frameworks, and the performance is evaluated through simulations. The results indicate the ability to efficiently sample spatial frequencies, while being lightweight and compact in size. Another attractive property of our architecture is the strong denoising ability for Gaussian noise.

With the increasing growth of multimedia data on the Internet, multimodal image aesthetic assessment has attracted a great deal of attention in the image processing community. However, traditional multimodal methods often have the following two problems: (1) Existing multimodal image aesthetic methods are based on the assumption that full modalities are available in all samples, which is unapplicable in most cases since textual information is more difficult to obtain. (2) They only fuse multimodal information at a single level and ignore their interaction at different levels. To address these two challenges, we proposed a novel framework termed Missing-Modility-Multimodal-Bert networks (MMMB). To achieve the completeness, we first generate the missing textual modality conditioned on the available visual modality. We then project the image features to the token space of the text, and use the transformer’s self-attention mechanism to make the two different modalities information interact at different levels for earlier and more fine-grained fusion, rather than only at the final layer. A large number of experiments on two large benchmark datasets in the field of image aesthetic quality evaluation: AVA and Photo.net demonstrate that the proposed model significantly improves image aesthetic assessment performance under both textual missing modality condition and full-modality condition.

Imaging past the diffraction limit is of significance to an optical system. Fourier ptychography (FP) is a novel coherent imaging technique that can achieve this goal and it is widely used in microscopic imaging. Most phase retrieval algorithms for FP reconstruction are based on Gaussian measurements which cannot extend straightforwardly to long range, sub-diffraction imaging setup because of laser speckle noise corruption. In this work, a new FP reconstruction framework is proposed for macroscopic visible imaging. When compared with existing research, the reweighted amplitude flow algorithm is adopted for better signal modeling, and the Regularization by Denoising (RED) scheme is introduced to reduce the effects of speckle. Experiments demonstrate that the proposed method can obtain state-of-the-art recovered results on both visual and quantitative metrics without increasing computation cost, and it is flexible for real imaging applications.

As an important error in star centroid location estimation, the systematic error greatly restricts the accuracy of the three-axis attitude supplied by a star sensor. In this paper, an analytical study about the behavior of the systematic error in the center of mass (CoM) centroid estimation method under different Gaussian widths of starlight energy distribution is presented by means of frequency field analysis and numerical simulations. Subsequently, an optimized extreme learning machine (ELM) based on the bat algorithm (BA) is adopted to predict the systematic error of the actual star centroid position and then compensate the systematic error from the CoM method. In the BA-ELM model, the input weights matrix and hidden layer biases parameters are encoded as microbat’s locations and optimized by utilizing the strong global search capacity of BA, which significantly improves the performance of ELM in terms of prediction accuracy. The simulation result indicates that our method can reduce the systematic error to less than 3.0 × 10⁻⁷ pixels, and its compensation accuracy is two or three orders of magnitude higher than that of other methods for estimating a star centroid location under a 3 × 3 pixel sampling window.

Imaging correlography, an effective method for long-distance imaging, recovers an object using only the knowledge of the Fourier modulus, without needing phase information. It is not sensitive to atmospheric turbulence or optical imperfections. However, the unreliability of traditional phase retrieval algorithms in imaging correlography has hindered their development. In this work, we join imaging correlography and ptychography together to overcome such obstacles. Instead of detecting the whole object, the object is measured part-by-part with a probe moving in a ptychographic way. A flexible optimization framework is proposed to reconstruct the object rapidly and reliably within a few iterations. In addition, novel image space denoising regularization is plugged into the loss function to reduce the effects of input noise and improve the perceptual quality of the recovered image. Experiments demonstrate that four-fold resolution gains are achievable for the proposed imaging method. We can obtain satisfactory results for both visual and quantitative metrics with one-sixth of the measurements in the conventional imaging correlography. Therefore, the proposed imaging technique is more suitable for long-range practical applications.

Image aesthetic quality assessment (IAQA) has aroused considerable interest in recent years and is widely used in various applications, such as image retrieval, album management, chat robot and social media. However, existing methods need an excessive amount of labeled data to train the model. Collecting the enormous quantity of human scored training data is not always feasible due to a number of factors, such as the expensiveness of the labeling process and the difficulty in correctly classifying data. Previous studies have evaluated the aesthetic of a photo based only on image features, but have ignored the criterion bias associated with the themes. In this work, we present a new theme-aware semi-supervised image quality assessment method to address these difficulties. Specifically, the proposed method consists of two steps: a representation learning step and a label propagation step. In the representation learning step, we propose a robust theme-aware attention network (TAAN) to cope with the theme criterion bias problem. In the label propagation step, we use preliminary trained TAAN by step one to extract features and utilize the label propagation with a cumulative confidence (LPCC) algorithm to assign pseudo-labels to the unlabeled data. This enables use of both labeled and unlabeled data to train the TAAN model. To the best of our knowledge, this is the first time that a semi-supervised learning method to address image aesthetic assessment problems has been studied. We evaluate our approach on three benchmark datasets and show that it can achieve almost the same performance as a fully supervised learning method for a small number of samples. Furthermore, we show that our semi-supervised approach is robust to using varying quantities of labeled data.