We present a new 360 camera design for creating 360 videos for immersive VR experiences. We place eight fish-eye lenses on a circle. Four interlaced fish-eye lenses are slightly re-oriented up in order to cover the scene above. To the best of our knowledge, our camera has the smallest diameter of any existing stereo multi-lens rig on the market. Our camera can be used to create 2D, 3D and 6DoF multi-format 360 videos. Due to its compact design, the minimum safe distance of our new camera is very short (approximately 30cm). This allows users to create special intimate immersive experiences. We also propose to characterize the camera design using the fractal ratio of the distance of adjacent view points and interpupillary distance. While most early camera designs have fractal ratio or =1, our camera has the fractal ratio . Moreover, with adjustable rendering interpupillary distance, our camera can be used to flexibly control the interpupillary distance for creating 3D 360 videos. Our camera design has high fault tolerance and it can continue operating properly even in the event of the failure of some individual lenses.

Memory bandwidth has become a bottleneck that impedes performance improvement during the parallelism optimization of the datapath. Memory partitioning is a practical approach to reduce bank-level conflicts and increase the bandwidth on a field-programmable gate array. In this work, we propose a memory partitioning approach for multi-pattern data access. First, we propose to combine multiple patterns into a single pattern to reduce the complexity of multi-pattern. Then, we propose to perform data reuse analysis on the combined pattern to find data reuse opportunities and the non-reusable data pattern. Finally, an efficient bank mapping algorithm with low complexity and low overhead is proposed to find the optimal memory partitioning solution. Experimental results demonstrated that compared to the state-of-the-art method, our proposed approach can reduce the number of block RAMS by 58.9% on average, with 79.6% reduction in SLICEs, 85.3% reduction in LUTs, 67.9% in reduction Flip-Flops, 54.6% reduction in DSP48Es, 83.9% reduction in SRLs, 50.0% reduction in storage overhead, 95.0% reduction in execution time, and 77.3% reduction in dynamic power consumption on average. Meanwhile, the performance can be improved by 14.0% on average.

Memory partitioning has been widely adopted to increase the memory bandwidth. Data reuse is a hardware-efficient way to improve data access throughput by exploiting locality in memory access patterns. We found that for many applications in image and video processing, a global data reuse scheme can be shared by multiple patterns. In this paper, we propose an efficient data reuse strategy for multi-pattern data access. Firstly, a heuristic algorithm is proposed to extract the reuse information as well as find the non-reusable data elements of each pattern. Then the non-reusable elements are partitioned into several memory banks by an efficient memory partitioning algorithm. Moreover, the reuse information is utilized to generate the global data reuse logic shared by the multi-pattern. We design a novel algorithm to minimize the number of registers required by the data reuse logic. Experimental results show that compared with the state-of-the-art approach, our proposed method can reduce the number of required BRAMs by 62.2% on average, with the average reduction of 82.1% in SLICE, 87.1% in LUTs, 71.6% in Flip-Flops, 73.1% in DSP48Es, 83.8% in SRLs, 46.7% in storage overhead, 79.1% in dynamic power consumption, and 82.6% in execution time of memory partitioning. Besides, the performance is improved by 14.4%.

We present a new projection format and packing layout for 360 VR videos using octahedron mapping. A spherical video is projected onto an octahedron, where the upper and lower hemispheres correspond to the upper and lower half of the octahedron, respectively. Four regular triangles in the half of the octahedron, are transformed into isosceles right-angled triangles and packed into a square by remaining adjacent edges. Two equal squares resulted respectively from the upper and lower half of the octahedron, are placed side by side and adjoined by a common edge. This generates a 2:1 aspect ratio rectangle. We demonstrate that our new projection format and layout have advantages in uniformity of pixel density, internal continuity and rectangle aspect ratio while encoding 360 VR videos.