Image Capture and Display Based on Embedded Linux - Core

Available online at www.sciencedirect.com

Physics Procedia 25 (2012) 1141 – 1148

2012 International Conference on Solid State Devices and Materials Science

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Image Capture and Display Based on Embedded Linux Zhang Weigong, Di Suran, Zhang Yongxiang and Li Liming College of Information Engineering Capital Normal University Beijing, China

Abstract For the requirement of building a highly reliable communication system, SpaceWire was selected in the integrated electronic system. There was a need to test the performance of SpaceWire. As part of the testing work, the goal of this paper is to transmit image data from CMOS camera through SpaceWire and display real-time images on the graphical user interface with Qt in the embedded development platform of Linux & ARM. A point-to-point mode of transmission was chosen; the running result showed the two communication ends basically reach a consensus picture in succession. It suggests that the SpaceWire can transmit the data reliably.

© 2012 2011 Published Published by Elsevier Ltd. © B.V.Selection Selectionand/or and/orpeer-review peer-reviewunder underresponsibility responsibilityofof[name Garryorganizer] Lee Open access under CC BY-NC-ND license.

Keywords: SpaceWire bus; embedded Linux; image capture and display; CMOS camera; Qt

I. Introduction SpaceWire [1], which simplifies and standardizes the interconnection between heterogeneous devices, is a high-speed (2 Mbps to 200 Mbps), point to point, full-duplex serial bus standard developed by ESA. SpaceWire technology, which has been successfully used on many space missions by ESA, NASA & JAXA, is now in the forefront of aerospace technology bus. In order to provide a safe and reliable communication platform for integrated electronic system, SpaceWire was selected as the communication protocol based on actual mission requirements. How does SpaceWire behave in simulation environment for the integrated electronic system? It is a critical task to know during the project study whether the performance of its network communications speed achieves the goal no slower than 300 Mbps. Therefore, the feasibility and effectiveness of SpaceWire for use on satellite communications must be verified so as to provide the basis for its application on satellites. As part of verification, there is a need to use SpaceWire to transmit image data the camera captured and display it on some widget. To do this, the 1

This work is supported by NNSFC Grant #60873006 and Beijing MCESTD Grant #KM 200910028019.

1875-3892 © 2012 Published by Elsevier B.V. Selection and/or peer-review under responsibility of Garry Lee Open access under CC BY-NC-ND license. doi:10.1016/j.phpro.2012.03.211

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Zhang Weigong et al. / Physics Procedia 25 (2012) 1141 – 1148

whole paper is divided into four parts: a brief introduction on the hardware and software developmentplatform environment was given first; then a flow chart was followed, meanwhile, a detailed analysis of how to implement the key modules in the chart was given; after that the running result was shown; and finally, summary and future work were put forward. 2. Development-platform

2.1 System Hardware Architecture The system consists of two nodes: node1 and node2, where node1 is the sending node and node2 is the receiving node. The hardware of the former is composed of three parts: the CMOS camera, the ARM development board and the smart SpaceWire node controller. Among them, the development board has an external 3.5 inch true color screen with the resolution of 240*320; the CPU selected, with a CMOS camera interface, belongs to Samsung's ARM family; the development board connects with the external CMOS camera through CON4 interface and in the meantime connects with the SpaceWire node controller through the system bus interface CON5. It is supposed that the data processing each time for SpaceWire node controller can not exceed 4 KB. The receiving node just has no camera compared to the sending node. Two nodes connects with each other through the way of point-to-point, i.e. they interconnect through SpaceWire interface on the node controller; the current maximum transmission rate of the data link is 33 Mbps. The entire system hardware architecture is shown in Fig. 1.

Fig. 1 System Hardware Architecture

2.2 Software Running Environment Linux has many advantages, such as a small kernel, high efficiency, open source, cross-platform, easy-toconfigure and so on. And Qtopia, developed by Trolltech for consumer electronic devices using embedded Linux operating system, is a comprehensive application platform. It includes a complete application layer, a flexible user interface, windows operating system, starting programs for applications, and developing framework. Because of all those features and advantages above, Linux + Qtopia 2.2.0 GUI operating environment were chosen as the running environment for the development board, and version of ARM-Linux kernel is 2.6.29. 3. Design

Zhang Weigong et al. / Physics Procedia 25 (2012) 1141 – 1148

3.1 Flow Control As mentioned earlier, the entire system takes point-to-point transmission mode, which involves two nodes, a sender and a receiver. The sender continuously collects a frame of data each time, then processes it, next shows the result processed on a widget in the local machine, after that, determines whether to send the result to the receiver. This process continues until the end. However, the control of the receiver is relatively simple. As long as the reception conditions are met, the receiver receives the image data frame by frame and displays it. The flow controls of both ends are shown in Fig. 2. 7KHVHQGHU EHJLQ

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