Weigong Zhang

A high dynamic range complementary metal-oxide-semiconductor (CMOS) camera using multi-slope response and an image reconstruction algorithm

Dynamic range is a critical figure of merit for an imaging system; it describes the observable range of brightness. This paper introduces the design of a complementary metal-oxide-semiconductor (CMOS) camera for astronomical imaging using the IBIS5 sensor. The camera achieves a high dynamic range by multi-slope response using variable reset voltages. A method to convert an image captured in multi-slope response into a linear image, and thus obtain higher contrast, is developed and analysed. Finally, observation results of the sun and the moon with this camera are presented. The results confirm the practicality of this camera and the image reconstruction method in scientific applications.

Design of Panoramic Mosaic Camera Based on FPGA Using Optimal Mosaic Algorithm

It was the panoramic technology that extensively used in the scopes of Video Compression, Virtual Reality, Pathology of Medical Science, Teleconference System and so on. Panoramic mosaic perspective, taking both full view images of a sight of view, is a critical figure of merit for a panoramic system. This paper introduces the design of a panoramic mosaic camera, which is used in the special circumstances that required both with view and ambulant ability. The camera achieves panoramic perspective by analyzing optical structure and using multiple image sensors. A mosaic algorithm to rapidly locate the coordinate of overlapped area and to obtain real-time performance in embedded system is analyzed and optimized. In addition, the Ethernet interface, to send the panoramic view to the remote terminal, is also discussed. Finally we present the evaluation results, showing that this camera can satisfy the requirement of panoramic systems.

Design and evaluation of a high-performance charge coupled device camera for astronomical imaging

The Space Solar Telescope (SST) is the first Chinese space astronomy mission. This paper introduces the design of a high-performance 2K × 2K charge coupled device (CCD) camera that is an important payload in the Space Solar Telescope. The camera is composed of an analogue system and a digital embedded system. The analogue system is first discussed in detail, including the power and bias voltage supply circuit, power protection unit, CCD clock driver circuit, 16 bit A/D converter and low-noise amplifier circuit. The digital embedded system integrated with an NIOS II soft-core processor serves as the control and data acquisition system of the camera. In addition, research on evaluation methods for CCDs was carried out to evaluate the performance of the TH7899 CCD camera in relation to the requirements of the SST project. We present the evaluation results, including readout noise, linearity, quantum efficiency, dark current, full-well capacity, charge transfer efficiency and gain. The results show that this high-performance CCD camera can satisfy the specifications of the SST project.

Research on a New Real-Time Bad Block Replacement Algorithm

The characters of FLASH memory are low-power, long-lived, deep storage density, adapted to strict environment, nonvolatile and the price is decreased, because of these reasons, it is wildly used. However, there are some inherent particularities: low writing speed, bad blocks exist when produced and could generated with using and so on. A new bad block management algorithm is proposed in this paper based on the application of NAND FLASH, and it improved the efficiency and ensured the data continuity. The experiment in this paper is based on NAND FLASH which is non-volatile memory. The NAND FLASH is composed by several storage unit blocks, and every storage unit block which is the least erasing unit includes several storage pages. The storage page is the least unit to write data. Compared with normal memory the reading speed of FLASH is faster, but the data must be erased with storage unit block before writing accord page order. There are some initial invalid blocks (bad block) in NAND FLASH that the manufacturing company do not ensue its reliability. The bad blocks are allowed existing in end product because using NAND technology. The bad blocks do not affect the performance of the other blocks, but they should be masked by address mapping table in system. When chips produced, all parts except the area that save information of bad blocks are erased (the value is 0xFF). The bad blocks must be distinguished according the initial bad block information when designing system, and build bad blocks table. It needs to compare the block address which going to be operated with bad block address table, jumps if it is bad block. New bad blocks maybe produced when chips running, so these conditions should be considered in order to keep system reliability. If defaults were found in reading state register after writing data or block erasing operation, that means there are bad pages in block i.e. this is a bad block and its information should be saved into the bad block table.

Research on a method to extend dynamic range of CMOS APS

Dynamic range is a very important figure of merit to an imaging system since it decides the range of brightness we can observe. The paper first introduces the design of a CMOS sensor, which achieves high dynamic range by its dual slope response. And then a model is established to illustrate how the dual slope response works. A method to reconstruct the acquired image from multi-slope response to linear response over fully extended dynamic range is also developed and analyzed by simulations and experiments. In addition, the reconstruction error is discussed. Experimental tests were carried out using the extended dynamic range CMOS camera working in dual slope mode, and then the image was restored from dual slope response to linear response over fully extended dynamic range. The results show a favorable aspect of the CMOS imager with dual slope response and data restoration method in large dynamic range imaging.

Creating Affective Autonomous Characters Using Planning in Partially Observable Stochastic Domains

The ability to reason about and respond to their own emotional states can enhance the believability of Non-Player Characters (NPCs). In this paper, we use a Partially Observable Markov Decision Process (POMDP)-based framework to model emotion over time. A two-level appraisal model, involving quick and reactive vs. slow and deliberate appraisals, is proposed for the creation of affective autonomous characters based on POMDPs, wherein the probability of goal satisfaction is used in an appraisal and reappraisal process for emotion generation. We not only extend Probabilistic Computation Tree Logic (PCTL) for reasoning about the properties of emotional states based on POMDPs but also illustrate how four reactive (primary) emotions and nine deliberate (secondary) emotions can be derived by combining PCTL with the belief-desire theory of emotion. The results of an empirical study suggest that the proposed model can be used to create characters that appear to be more believable and more intelligent.

Research on Precise Synchronization for TMR Fault-Tolerant Embedded Computer

This article presents a precise synchronization algorithm based on status tracking and locking mechanism. Tracking execution state of triple computer and running state of time base counter through dual state machine not only can implement precise synchronization of TMR computer, making status synchronization precision and time-base synchronization precision below 30ns, but also save valuable interconnection resource, reduce implementation cost and other overhead of system resources.

A Circular Buffer Mode Design Based on BU-61580

Most of BU-61580 storage mode that used formerly transmitted and received data with single message mode. In this paper, we use the circular buffer mode to implement data receiving based on the single message mode, thus greatly improve the efficiency of data transmission. Keywords-1553B; circular buffer mode; RT; memroy management

Evaluation method and result of 4K×4K CCD sensor for LAMOST project

Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) is a 4 meter Schmidt system developing in China, with the aim of probing into the structure of the universe. It needs 32 high performance CCD cameras working in the spectral range of 370-900 nm. 4 K times 4 K CCD203_82 chip made by e2v technology is selected for the camera in LAMOST. The evaluation of E2V technology 4 K times 4 K CCD203_82 was carried out to check whether the chip can satisfy the performance requirements of LAMOST project. In this paper, parameter test methods and test facility are introduced first. The evaluation results are also presented, including dark current, full well capacity, charge transfer efficiency, gain, readout noise and linearity. The results show that the performances of CCD203_82 based on low noise CCD controller are excellent for night astronomical observation and achieve the specification of LAMOST project.