Department Publications

A 5-D depth–velocity filter is proposed for enhancing moving objects in noisy light field videos (LFVs) (also known as plenoptic videos). The proposed filter consists of an ultra-low complexity 5-D IIR depth filter and a 5-D FIR velocity filter. The 5-D IIR depth filter is employed to denoise a noisy LFV. The denoised LFV is then utilized to estimate the 3-D apparent velocity of the moving object of interest. The 5-D FIR velocity filter is designed based on the estimated 3-D apparent velocity and is used to enhance the moving object of interest while attenuating other interfering moving objects. Experimental results confirm the effectiveness of the proposed 5-D depth–velocity filter compared to previously reported 5-D depth–velocity filters.

A low-complexity 2-D FIR trapezoidal filter is proposed for enhancing broadband plane waves. Motivated by the design technique of 1-D interpolated FIR filters, the proposed filter is realized by cascading a low-complexity spatiallyupsampled 2-D FIR filter having a trapezoidal passband and a low-complexity 2-D FIR masking filter having a parallelogram passband. Experimental results confirm that the proposed filter provides 74% reduction of the computational-complexity compared to conventional 2-D FIR fan and conventional 2-D FIR trapezoidal filters without deteriorating the performance in enhancing 2-D broadband plane waves distorted by strong interference and noise signals.

Screen content coding (SCC) extension to High Efficiency Video Coding (HEVC) offers substantial compression efficiency over the existing HEVC standard for computer generated content. However, this gain in compression efficiency is achieved at the expense of further computational complexity with several resource hungry coding tools. Hence, extension of SCC to HEVC hardware encoders can be challenging. This paper presents resource efficient hardware designs for two key SCC tools, Intra Block Copy and Palette Coding. Moreover, a new hash search approach is proposed for Intra Block Copy, while a hardware friendly palette indices coding scheme is suggested for Palette Coding. These designs are targeted to achieve the throughput necessary for an 1080p 30 frames/s encoder, and incurs coding loss of 11.4% and 5.1% respectively in all intra configurations. The designs are synthesized for a Virtex-7 …

An ultra-low complexity three-dimensional (3-D) linear-phase infinite-extent impulse response (IIR) velocity filter is proposed for attenuating moving artifacts in videos while enhancing objects moving on smooth approximately-linear trajectories. The proposed 3-D linear-phase IIR velocity filter consists of an ultra-low complexity 3-D wide-angle linear-phase IIR cone filter bank between two two-dimensional (2-D) spatial variable-shift filters. The ultra-low complexity 3-D wide-angle linear-phase IIR cone filter bank consists of a one-dimensional (1-D) temporal modified discrete Fourier transform filter bank and 2-D spatial allpass, IIR highpass and allstop filters. A typical 3-D linear-phase IIR velocity filter of order , applied to enhance a heavily corrupted test video signal, requires only 26 real multiplications and 60 real additions to process a sample and provides a scene-complexity-independent signal-to …

A novel multidimensional spatio-temporal signal processing algorithm is proposed for depth-velocity filtering in 5-D light field videos along with a tutorial review of light field video spectra and the general architecture of associated 5-D depth-velocity filters. A 5-D FIR filter having a hyperfan-shaped passband which can selectively enhance the spectra of moving objects in light field videos based on their depth and motion trajectory is employed. A 5-D hyperfan-shaped passband is highly desired to achieve enhanced spatio-temporal selectivity over a wide range of lower frequencies. Experimental results are provided by using a light field videos captured using a Lytro light-field camera and mean structural similarity index is used to verify the effectiveness of the proposed 5-D FIR hyperfan depth-velocity filter.