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In this paper, we propose a symmetric series convolutional neural network (SS-CNN), which is a novel deep convolutional neural network (DCNN)-based super-resolution (SR) technique for ultrasound medical imaging. The proposed model comprises two parts: a feature extraction network (FEN) and an up-sampling layer. In the FEN, the low-resolution (LR) counterpart of the ultrasound image passes through a symmetric series of two different DCNNs. The low-level feature maps obtained from the subsequent layers of both DCNNs are concatenated in a feed forward manner, aiding in robust feature extraction to ensure high reconstruction quality. Subsequently, the final concatenated features serve as an input map to the latter 2D convolutional layers, where the textural information of the input image is connected via skip connections. The second part of the proposed model is a sub-pixel convolutional (SPC) layer, which up-samples the output of the FEN by multiplying it with a multi-dimensional kernel followed by a periodic shuffling operation to reconstruct a high-quality SR ultrasound image. We validate the performance of the SS-CNN with publicly available ultrasound image datasets. Experimental results show that the proposed model achieves an exquisite reconstruction performance of ultrasound image over the conventional methods in terms of peak signal-to-noise ratio (PSNR), and structural similarity index (SSIM), while providing compelling SR reconstruction time.

Digital displays and off-the-shelf smartphone cameras are the most common and promptly available electronic devices which have also been recently applied for data transmission and reception through optical medium in a wireless manner. In this paper, we propose a data embedding technique in display to camera communication (D2C) where the data is inserted into the mid-frequency region of a discrete cosine transform (DCT) domain image. The intended data in the form of modulated symbols are first multiplied with the predetermined embedding factor and then exponentially multiplied with the vector coefficients of the selected region. Extensive experiments considering receiver orientation, capture distance and angle were conducted in a real-world environment with the help of off-the-shelf smartphone camera and a digital display. We showed that the proposed technique offers fair peak signal to average ratio (PSNR) with robust bit error rate (BER) performance, while the data embedded on the image was not perceptible to human vision.

In this paper, we propose Deep D2C-Net, a novel display-to-camera (D2C) communications technique using deep convolutional neural networks (DCNNs) for data embedding and extraction with images. The proposed technique consists of fully end-to-end encoding and decoding networks, which respectively produce high-quality data-embedded images and enable robust data acquisition in the presence of optical wireless channel. For encoding, Hybrid layers are introduced where the concurrent feature maps of the intended data and cover images are concatenated in a feed-forward fashion; for decoding, a simple convolutional neural network (CNN) is utilized. We conducted experiments in a real-world environment using a smartphone camera and a digital display with multiple parameters, such as transmission distance, capture angle, display brightness, and resolution of the camera. Experimental results prove that Deep D2C-Net outperforms the existing state-of-the-art algorithms in terms of peak signal-to-noise ratio (PSNR) and bit error rate (BER), while the data-embedded image displayed on the screen yields high visual quality for the human eye.

Recently, digital displays and cameras have been extensively used as new data transmission and reception devices in conjunction with optical camera communication (OCC) technology. This paper presents three types of frequency-based data-embedding mechanisms for a display-to-camera (D2C) communication system, in which a commercial digital display transmits information and an off-the-shelf smartphone camera receives it. For the spectral embedding, sub-band coefficients obtained from a discrete cosine transform (DCT) image and predetermined embedding factors of three embedding mechanisms are used. This allows the data to be recovered from several types of noises induced in wireless optical channels, such as analog-to-digital (A/D) and digital-to-analog (D/A) conversion, rotation, scaling, and translation (RST) effects, while also maintaining the image quality to normal human eyes. We performed extensive simulations and real-world D2C experiments using several performance metrics. Through the analysis of the experimental results, it was shown that the proposed method can be considered as a suitable candidate for the D2C system in terms of the achievable data rate (ADR), peak signal-to-noise ratio (PSNR), and the bit error rate (BER).