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基于透射式液晶的电光特性, 设计和开发了一套基于液晶和数字处理器 (digital signal processor, DSP)的强光局部选通智能网络摄像机系统. 系统基于透射式液晶和DSP开发板(核心芯片TMS320DM642)技术, 利用DSP控制液晶驱动, 实现液晶单个像素透过率的控制, 将强光的透过率下降2个数量级; 该系统利用另一块DSP 开发板(核心芯片TMS320DM6437)实现将处理后的强光视频信号进行网络传输与实时存储到PC机中, 实现选通智能网络摄像. 该系统24 h所需存储硬盘容量8.648 Gbit, 所用液晶的延迟时间25.5 ms, 电路延迟时间17 μs. 在光强大于2.2×105 lx的强光照射下, 得到系统的选通视频实验结果. 结果表明该系统能解决强光下普通CCD高动态范围摄像机出现局部曝光过度而不能分辨细节的成像问题, 实现了CCD的高动态范围成像.Based on the electro-optical characteristics of the transmission-type liquid crystal (LC) and DSP (Digital Signal Processor, chip TMS320DM642) technology, a smart network camera system for partial gating strong light intensity is developed. An LC display driver is controlled by DSP to achieve light intensity transmittance of every single pixel in this system; the light intensity transmittance can be decreased by two orders of magnitude. In addition, the smart camera of video signal processed under a strong light can be transmitted through network transmission and real-time storage to PC by another DSP (chip TMS320DM6437). Thus the LC delay time is about 25.5 ms and the system circuit delay time is about 17 μs, while the storage hard disk capacity requires 8.648 Gbit in 24 h. Experimental images are taken by the prototype to shoot the simulated license plate illuminated by the strong light (greater than 2.2×105 lx). Results show that the imaging problems, viz the ordinary CCD camera may give partially overexposed images and cannot distinguish details under the strong light, are all solved and achieved a high dynamic range imaging by the prototype.
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Keywords:
- liquid crystal /
- DSP /
- light transmittance /
- high dynamic range imaging
[1] Tang Y H, Cao X G, Liu H C, Shepherd G G, Liu S L, Gao H Y, Yang X S, Wu Y, Wang S W 2012, Appl. Opt. 51 1968
[2] Gu L, Hu X D, Luo C Z, Xu Z 2002 Acta Phot. Sin. 31 12 (in Chinese) [谷林, 胡晓东, 罗长洲, 徐洲 2002 光子学报 31 12]
[3] Jing L X, Lv Z M, Xiong J W 2002 Opt. Precis. Eng. 10 588 (in Chinese) [金龙旭, 吕增明, 熊经武 2002 光学精密工程 10 588]
[4] Hu B L, Ma C W, Sun Y S 2002 Acta Phot. Sin. 31 504 (in Chinese) [胡炳梁, 马彩文, 孙益善 2002 光子学报 31 504]
[5] Estera J P, Sakdana M R 2003 SPIE 5079 212
[6] Estera J P, Sakdana M R 2003 SPIE 4796 60
[7] Debevec P E, Malik J 2008 ACM Siggraph 2008 Classes (Beijing) 2008 p31
[8] Liu C, Hu L F, Mu Q Q 2012 Acta Phys. Sin. 61 129501 (in Chinese) [刘超, 胡立发, 穆全全 2012 61 129501]
[9] Zheng J H, Zhong Y W, Wen K 2010 Acta Phys. Sin. 59 1831 (in Chinese) [郑继红, 钟阳万, 温垦 2010 59 1831]
[10] Tang Y H, Zhang R X, Gao H Y, Liu K, Zhao G X, Yang X S, Li Q, Liang Y, Ye N, Liu H C, Liu S L 2010 Opt. Express 18 10616
[11] Tang Y H, Yang X S, Gao H Y, Wu Y, Wang S W, Cao X G, Jia W L 2013 J. Quant Spectrosc Radiat Transf 122 87
[12] Tang Y H, Zhang R X, Liu H C, Liu S L, Liu K, Gao H Y 2010 J. Liquid Crystals and Display 25 200 (in Chinese) [唐远河, 张瑞霞, 刘汉臣, 刘术林, 刘锴, 郜海阳 2010 液晶与显示 25 200]
[13] Tang Y H, Wu Y, Yang X S, Wang S W 2013 Patent 201310011154.6 [2013.1.11]
[14] Pescador F, Maturana G, Garrido M, Juarez E, Sanz C 2009 IEEE Transactions on Consumer Electronics 55 205
[15] Tang Y H, Liu H C 1999 Practical technology and art of photography (Xian: Xian MapPress) (in Chinese) 27 [唐远河, 刘汉臣 1999 实用摄影技术与艺术 (西安: 西安地图出版社) 第27页]
[16] Zhao J L, Ren G J 2006 J. Liquid Crystals and Display 21 384 (in Chinese) [赵阶林, 任广军 2006 液晶与显示 21 384]
[17] Liu Y J, Xu K S, Zhang B 2004 Acta Phys. Sin. 53 1850 (in Chinese) [刘言军, 徐克璹, 张斌 2004 53 1850]
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[1] Tang Y H, Cao X G, Liu H C, Shepherd G G, Liu S L, Gao H Y, Yang X S, Wu Y, Wang S W 2012, Appl. Opt. 51 1968
[2] Gu L, Hu X D, Luo C Z, Xu Z 2002 Acta Phot. Sin. 31 12 (in Chinese) [谷林, 胡晓东, 罗长洲, 徐洲 2002 光子学报 31 12]
[3] Jing L X, Lv Z M, Xiong J W 2002 Opt. Precis. Eng. 10 588 (in Chinese) [金龙旭, 吕增明, 熊经武 2002 光学精密工程 10 588]
[4] Hu B L, Ma C W, Sun Y S 2002 Acta Phot. Sin. 31 504 (in Chinese) [胡炳梁, 马彩文, 孙益善 2002 光子学报 31 504]
[5] Estera J P, Sakdana M R 2003 SPIE 5079 212
[6] Estera J P, Sakdana M R 2003 SPIE 4796 60
[7] Debevec P E, Malik J 2008 ACM Siggraph 2008 Classes (Beijing) 2008 p31
[8] Liu C, Hu L F, Mu Q Q 2012 Acta Phys. Sin. 61 129501 (in Chinese) [刘超, 胡立发, 穆全全 2012 61 129501]
[9] Zheng J H, Zhong Y W, Wen K 2010 Acta Phys. Sin. 59 1831 (in Chinese) [郑继红, 钟阳万, 温垦 2010 59 1831]
[10] Tang Y H, Zhang R X, Gao H Y, Liu K, Zhao G X, Yang X S, Li Q, Liang Y, Ye N, Liu H C, Liu S L 2010 Opt. Express 18 10616
[11] Tang Y H, Yang X S, Gao H Y, Wu Y, Wang S W, Cao X G, Jia W L 2013 J. Quant Spectrosc Radiat Transf 122 87
[12] Tang Y H, Zhang R X, Liu H C, Liu S L, Liu K, Gao H Y 2010 J. Liquid Crystals and Display 25 200 (in Chinese) [唐远河, 张瑞霞, 刘汉臣, 刘术林, 刘锴, 郜海阳 2010 液晶与显示 25 200]
[13] Tang Y H, Wu Y, Yang X S, Wang S W 2013 Patent 201310011154.6 [2013.1.11]
[14] Pescador F, Maturana G, Garrido M, Juarez E, Sanz C 2009 IEEE Transactions on Consumer Electronics 55 205
[15] Tang Y H, Liu H C 1999 Practical technology and art of photography (Xian: Xian MapPress) (in Chinese) 27 [唐远河, 刘汉臣 1999 实用摄影技术与艺术 (西安: 西安地图出版社) 第27页]
[16] Zhao J L, Ren G J 2006 J. Liquid Crystals and Display 21 384 (in Chinese) [赵阶林, 任广军 2006 液晶与显示 21 384]
[17] Liu Y J, Xu K S, Zhang B 2004 Acta Phys. Sin. 53 1850 (in Chinese) [刘言军, 徐克璹, 张斌 2004 53 1850]
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