高效率的嵌入式自然影像監控系統之硬體設計

Hardware Design of High-Efficiency Embedded Natural Image Surveillance System

魏成恩(Cheng-En Wei)

指導教授 ： 江正雄

淡江大學/工學院/電機工程學系碩士班/碩士(2020年)

https://doi.org/10.6846/TKU.2020.00688

摘要

監控系統( Surveillance System )雖能忠於現實的場景擷取出影像，但是擷取出的影像不一定具有鮮明的紋理表現以及亮度正規化的特性能夠提供給人體視覺系統HVS( Human Visual System , HVS )視覺愉悅感。有鑑於此，不少市面上的監控系統也已經配合市場需求增加了對比增強( Contrast Enhancement )的功能。現今市面上監控系統的產品雖具有對比增強的架構，但是犧牲了監控系統必要的即時處理( Real-Time )的效能，造成記憶體( Memory )過大和運算時間( Computing-Time )過長。因此本文透過改良式的參數導向直方圖等化( Parametric-Oriented Histogram Equalization , POHE )，透過counter的方法解決原始POHE的記憶體的大量使用以及LUT( Look-UP Table )的方法加速了運算速度，達成及時處理(Real-Time)的特性以利監控系統的後續使用。本文將以改良式的參數導向直方圖等化POHE 架構，保持即時處理的特性並且強化影像的細節和亮度正規化，實現在Altera DE2系列的 DE2i-150 FPGA Development Board上。

關鍵字

監控系統 ； 對比增強 ； 直方圖等化 ； 即時處理 ； 參數導向直方圖等化

並列摘要

Although a surveillance system can capture images accurately according to the actual scene, the captured images do not necessarily have sharp texture expression and brightness normalization characteristics, which can provide human visual system with visual pleasure sense. In order to solve the drawbacks, currently many monitoring systems have added the Contrast Enhancement function to meet the market needs. Although the monitoring systems on the market today have a contrast-enhanced scheme, they may sacrifice real-time performance required by the monitoring system due to too large memory needed and too much computing time. Therefore, in this work, we use an improved parametric-oriented histogram equalization (POHE) to enhance the contrast of images. Conventional POHE may use massive memory, but the proposed improved POHE uses a counter to overcome massive memory usage problems. We also employ the look-up table (LUT) technique to accelerate the calculation speed. Therefore, real-time processing is achieved to facilitate the subsequent use of the monitoring system. Besides, this research uses an improved POHE architecture to maintain the characteristics of real-time processing, and enhance the detail and brightness normalization of the image. We implement the modified POHE on DE2i-150 FPGA Development Board of the Altera DE2 series. The emulation results prove the proposed POHE can enhance the contrast of an image efficiently.

並列關鍵字

Surveillance System ； Contrast Enhancement ； Histogram Equalization ； Real-Time Processing ； Parametric-Oriented Histogram Equalization

參考文獻

[1]https://zh.wikipedia.org/wiki/%E5%9B%BE%E5%83%8F%E4%BC%A%E6%84%9F%E5%99%A

[2]https://zh.wikipedia.org/wiki/%E6%84%9F%E5%85%89%E8%80%A6%E5%90%88%E5%85%83%E4%BB%B6

[3]https://zh.wikipedia.org/wiki/%E4%BA%92%E8%A3%9C%E5%BC%8%E9%87%91%E5%B1%AC%E6%B0%A7%E5%8C%96%E7%89%A9%E5%8D%8A%E5%B0%8E%E9%AB%94

[4] http://kcs.kcjh.ptc.edu.tw/~spt/computer/digital-image/CCD-CMOS.htm

[5]S.Patel and M.Goswami ” Comparative analysis of Histogram Equalization techniques” 2014 International Conference on Contemporary Computing and Informatics (IC3I), Mysore, India.