Modern smartphone cameras can match traditional DSLR cameras in many areas thanks to the introduction of camera arrays and multi-frame processing. Among all types of DSLR effects, the narrow depth of field (DoF) or so called bokeh probably arouses most interest. Today's smartphones try to overcome the physical lens and sensor limitations by introducing computational methods that utilize a depth map to synthesize the narrow DoF effect from all-in-focus images. However, a high quality depth map remains to be the key differentiator between computational bokeh and DSLR optical bokeh. Empowered by a novel wavelet synthesis network architecture, we have greatly narrowed the gap between DSLR and smartphone camera in terms of the bokeh more than ever before. We describe three key Modern smartphone cameras can match traditional digital single lens reflex (DSLR) cameras in many areas thanks to the introduction of camera arrays and multi-frame processing. Among all types of DSLR effects, the narrow depth of field (DoF) or so called bokeh probably arouses most interest. Today's smartphones try to overcome the physical lens and sensor limitations by introducing computational methods that utilize a depth map to synthesize the narrow DoF effect from all-in-focus images. However, a high quality depth map remains to be the key differentiator between computational bokeh and DSLR optical bokeh. Empowered by a novel wavelet synthesis network architecture, we have narrowed the gap between DSLR and smartphone camera in terms of bokeh more than ever before. We describe three key enablers of our bokeh solution: a synthetic graphics engine to generate training data with precisely prescribed characteristics that match the real smartphone captures, a novel wavelet synthesis neural network (WSN) architecture to produce unprecedented high definition disparity map promptly on smartphones, and a new evaluation metric to quantify the quality of the disparity map for real images from the bokeh rendering perspective. Experimental results show that the disparity map produced from our neural network achieves much better accuracy than the other state-of-the-art CNN based algorithms. Combining the high resolution disparity map with our rendering algorithm, we demonstrate visually superior bokeh pictures compared with existing top rated flagship smartphones listed on the DXOMARK mobiles.

This paper investigates the problem of communicating video over a broadcast channel. The broadcast channel is expressed in terms of the channel capacity that exists between the transmitter and each receiver in the broadcast area-Shannon's separation theorem does not apply for video communication over this class of channels. Digital (discrete time, discrete amplitude) and hybrid (discrete time, discrete/continuous amplitude) transmission and video coding methods are discussed. Joint source and channel coding principles are employed to effectively couple these methods to form efficient systems for communicating video over broadcast channels. A framework is presented for characterizing and bounding the performance of these systems; the results lead to interesting directions for future work.

This paper describes a new HDTV system that applies joint multiresolution (MR) source and channel coding to efficiently use the available radio spectrum. Hybrid analog/digital MR channel modulation provides the benefits of digital source coding and the more efficient spectrum usage of analog transmission. Nonuniform spacing of the digital signaling levels provides MR delivery of the digital components while spread-spectrum processing permits MR delivery of the analog components. Error correction coding and OFDM channel modulation deliver the MR service in widely varying channel conditions. Simulation results demonstrate performance in various regions of the service area.>

A scalable source coder was designed for a hybrid HDTV terrestrial broadcasting system. The hybrid combination of analog and digital methods allows for both high video compression ratios and efficient utilization of the available channel capacity. Efficient channel utilization enables closer receivers to decode high quality video, and allows further receivers to decode natural looking, though lower quality video. The system uses joint source/channel coding to deliver different video components with degrees of integrity reflecting their perceptual importance. Motivation is given for hybrid transmission and analog/digital coding methods. Details of the scalable source coder are provided with a description of its key features, which include pyramid filtering and hybrid video coding. Furthermore, fundamental differences between conventional digital video compression schemes and the proposed scalable hybrid approach are highlighted. Finally, frames of video produced by a computer simulation of the hybrid HDTV system are shown, demonstrating the feasibility of such a system.>