1. S. Vedula, O. Senouf, A. M. Bronstein, O. V. Michailovich, M. Zibulevsky, Towards CT-quality ultrasound imaging using deep learning, arXiv:1710.06304 details

    Towards CT-quality ultrasound imaging using deep learning

    S. Vedula, O. Senouf, A. M. Bronstein, O. V. Michailovich, M. Zibulevsky

    The cost-effectiveness and practical harmlessness of ultra- sound imaging have made it one of the most widespread tools for medical diagnosis. Unfortunately, the beam-forming based image formation produces granular speckle noise, blur- ring, shading and other artifacts. To overcome these effects, the ultimate goal would be to reconstruct the tissue acoustic properties by solving a full wave propagation inverse prob- lem. In this work, we make a step towards this goal, using Multi-Resolution Convolutional Neural Networks (CNN). As a result, we are able to reconstruct CT-quality images from the reflected ultrasound radio-frequency(RF) data obtained by simulation from real CT scans of a human body. We also show that CNN is able to imitate existing computationally heavy despeckling methods, thereby saving orders of magni- tude in computations and making them amenable to real-time applications.

    O. Litany, T. Remez, A. Bronstein, Cloud Dictionary: Sparse coding and modeling for point clouds, arXiv:1612.04956 details

    Cloud Dictionary: Sparse coding and modeling for point clouds

    O. Litany, T. Remez, A. Bronstein

    With the development of range sensors such as LIDAR and time-of-flight cameras, 3D point cloud scans have become ubiquitous in computer vision applications, the most prominent ones being gesture recognition and autonomous driving. Parsimony-based algorithms have shown great success on images and videos where data points are sampled on a regular Cartesian grid. We propose an adaptation of these techniques to irregularly sampled signals by using continuous dictionaries. We present an example application in the form of point cloud denoising.

    T. Remez, O. Litany, R. Giryes, A. Bronstein, Deep class-aware denoising, arXiv:1701.01698 details

    Deep class-aware denoising

    T. Remez, O. Litany, R. Giryes, A. Bronstein

    The increasing demand for high image quality in mobile devices brings forth the need for better computational enhancement techniques, and image denoising in particular. At the same time, the images captured by these devices can be categorized into a small set of semantic classes. However simple, this observation has not been exploited in image denoising until now. In this paper, we demonstrate how the reconstruction quality improves when a denoiser is aware of the type of content in the image. To this end, we first propose a new fully convolutional deep neural network architecture which is simple yet powerful as it achieves state-of-the-art performance even without be- ing class-aware. We further show that a significant boost in performance of up to 0.4 dB PSNR can be achieved by making our network class-aware, namely, by fine-tuning it for images belonging to a specific semantic class. Relying on the hugely successful existing image classifiers, this research advocates for using a class-aware approach in all image enhancement tasks.

    T. Remez, O. Litany, R. Giryes, A. Bronstein, Deep convolutional denoising of low-light images, arXiv:1701.01687 details

    Deep convolutional denoising of low-light images

    T. Remez, O. Litany, R. Giryes, A. Bronstein

    Poisson distribution is used for modeling noise in photon-limited imaging. While canonical examples include relatively exotic types of sensing like spectral imaging or astronomy, the problem is relevant to regular photography now more than ever due to the booming market for mobile cameras. Restricted form factor limits the amount of absorbed light, thus computational post-processing is called for. In this paper, we make use of the powerful framework of deep convolutional neural networks for Poisson denoising. We demonstrate how by training the same network with images having a specific peak value, our denoiser outperforms previous state-of-the-art by a large margin both visually and quantitatively. Being flexible and data-driven, our solution resolves the heavy ad hoc engineering used in previous methods and is an order of magnitude faster. We further show that by adding a reasonable prior on the class of the image being processed, another significant boost in performance is achieved.