Depth information extraction with an aperture-rotating camera

This paper focuses on extracting depth information with an aperture-rotating camera. Compared with previous work, the proposed method is applicable for arbitrary rotation angle by making use of pixel registration to get pixel shift angle, and calculating the pixel shift along this angle. Besides, consumption time for shift angle is reduced by means of sampling. Compared with point-by-point method, the proposed method reduces the computation time from about 1 h to 1 min for a 15-megapixel image. Experimental results of a scene named “bottles” show that the depth value has a margin of error of 5%. Proposed method makes it possible to extract depth information with a single camera and expands the application of DSLR camera.     

捷联寻北信号采集系统研究

基于捷联寻北信号采集系统,提出了一种在不同地理纬度下准确获得陀螺数据拟合曲线的方法。首先计算得出了在不同地理纬度下动调陀螺输出的电流大小,根据其变化调整信号采集模块的采样电阻值,设计了基于数字电位器的自调整采样电阻系统;然后数据处理系统根据采集到的陀螺信号自动计算工作地点的地理纬度,自调整采样电阻系统通过地理纬度自动设置采样电阻的阻值,进而获得准确的数据拟合曲线。本方法确保了寻北仪在不同地理纬度时满足寻北精度要求,适应性强,稳定性高。     

Asynchronous sampling for ultrafast experiments with low momentum compaction at the ANKA ring

A high‐repetition‐rate pump–probe experiment is presented, based on the asynchronous sampling approach. The low‐α mode at the synchrotron ANKA can be used for a time resolution down to the picosecond limit for the time‐domain sampling of the coherent THz emission as well as for hard X‐ray pump–probe experiments, which probe structural dynamics in the condensed phase. It is shown that a synchronization of better than 1 ps is achieved, and examples of phonon dynamics of semiconductors are presented.     

采用树脂透镜的掌纹图像采集光学系统设计

为了获得高分辨率、高对比度和低畸变的掌纹图像,同时实现系统的轻量化和高性价比,本文基于全反射原理,采用树脂材料设计了一款由6片镜构成双远心光路的掌纹采集光学系统。树脂材料的选用减轻了光学系统的总重量;基于光的全反射原理的系统设计增强了掌纹图像的对比度;选择双远心光学结构,便于对倾斜物面所产生的梯形畸变进行矫正。对所设计光学系统的成像质量分析表明,该系统所有视场的光学传递函数（MTF）在Nyquist频率228 lp/mm处均达0.55以上,畸变〈0.14%。设计的光学系统可以采集120 mm×160 mm的手掌区域,实际手掌面上的分辨率达到500dpi,采集的掌纹图像分辨率达到8.0×106 pixel,满足了实际采集的要求。     

钢球质量监测最佳抽检方案的确定

本文介绍概率抽样法在钢球生产过程中的应用,通过此法确定钢球生产中各工序质量监测的最佳抽检方案,以确保产品被接受的概率最大。     

Localized Frames Are Finite Unions of Riesz Sequences

It is shown that every localized frame is a finite union of Riesz sequences. This is a partial solution to a question of Feichtinger.     

GS-221高速摄影测量仪测角信息的采集与处理

在GS-221高速摄影测量仪中,测角信息采集与处理速度的快慢是重要性能指标之一。本文讨论了如何在尽可能短的时间内对测角信息进行采集和处理的软件实现方法。     

Auxiliary field loop expansion of the effective action for a class of stochastic partial differential equations

We present an alternative to the perturbative (in coupling constant) diagrammatic approach for studying stochastic dynamics of a class of reaction diffusion systems. Our approach is based on an auxiliary field loop expansion for the path integral representation for the generating functional of the noise induced correlation functions of the fields describing these systems. The systems we consider include Langevin systems describable by the set of self interacting classical fields ?_i(x,t)${?}_i(x,t)$ in the presence of external noise η_i(x,t)${\eta }_i(x,t)$, namely (∂_t−ν∇²)?−F[?]=η$({\partial }_t-\nu {\nabla }^2)?-F\left[?\right]=\eta$, as well as chemical reaction annihilation processes obtained by applying the many-body approach of Doi–Peliti to the Master Equation formulation of these problems. We consider two different effective actions, one based on the Onsager–Machlup (OM) approach, and the other due to Janssen–deGenneris based on the Martin–Siggia–Rose (MSR) response function approach. For the simple models we consider, we determine an analytic expression for the Energy landscape (effective potential) in both formalisms and show how to obtain the more physical effective potential of the Onsager–Machlup approach from the MSR effective potential in leading order in the auxiliary field loop expansion. For the KPZ equation we find that our approximation, which is non-perturbative and obeys broken symmetry Ward identities, does not lead to the appearance of a fluctuation induced symmetry breakdown. This contradicts the results of earlier studies.