Figure 1: Some images rendered using the kd-trees generated by our method. The resolution is 1024 × 1024. AbstractKD-tree is one of the most efficient acceleration data structures for ray tracing. In this paper, we present a kd-tree construction algorithm that is precisely SAH-optimized and runs entirely on GPU. We construct the tree nodes in breadth-first order. In order to precisely evaluate the SAH cost, we design a parallel scheme based on the standard parallel scan primitive to count the triangle numbers for all split candidates, and a bucket-based algorithm to sort the AABBs (axis-aligned bounding box) of the clipped triangles of the child nodes. The proposed parallel algorithms can be mapped well to GPU's streaming architecture. The experiments showed that our algorithm can produce the highest quality kd-tree as the off-line CPU algorithms, but runs faster than multi-core CPU algorithms and the GPU SAH BVH-Tree algorithm.

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Abstract- Index Terms J J X Y Z ′ ′ ′A A R t R t s t t x y s t t t c σ δ 2) Impact of Jammer Position on Limit of Azimuth Resolution:

Various jamming techniques have been developed to prevent interferometric synthetic aperture radar from effective detection and observation. In this paper, a thorough analysis of the jamming effects on correlation and interferometric phase is provided. To derive the jamming result, a general signal model for the interference is first presented and the corresponding imaging results are produced through the range-Doppler algorithm. Then, the impacts of the interference on correlation are analyzed. The non-center located jammer decreases the correlation seriously due to the low correlation of the interference. However, the center located jammer clearly increases the correlation when the input jamming-to-signal ratio is large enough. Finally, the jammed interferometric phases for different jammer positions are discussed. It shows that the non-center located jammer results in large phase errors, while for the center located jammer, the interferometric phase approaches a constant. The effects of interference are demonstrated by simulated data based on the TerraSAR system.

The quality of an interferogram, which is limited by various phase noise, will greatly affect the further processes of InSAR, such as phase unwrapping. Interferometric SAR (InSAR) geophysical measurements’, such as height or displacement, phase filtering is therefore an essential step. In this work, an improved Goldstein interferogram filter is proposed to suppress the phase noise while preserving the fringe edges. First, the proposed adaptive filter step, performed before frequency estimation, is employed to improve the estimation accuracy. Subsequently, to preserve the fringe characteristics, the estimated fringe frequency in each fixed filtering patch is removed from the original noisy phase. Then, the residual phase is smoothed based on the modified Goldstein filter with its parameter alpha dependent on both the coherence map and the residual phase frequency. Finally, the filtered residual phase and the removed fringe frequency are combined to generate the filtered interferogram, with the loss of signal minimized while reducing the noise level. The effectiveness of the proposed method is verified by experimental results based on both simulated and real data.