即時影像對比度增強演算法與晶片設計

Real-Time Image Contrast Enhancement Algorithm and Chip Design

張嘉恩(Chia-En Chang)

指導教授 ： 陳世綸

中原大學/電機資訊學院/電子工程研究所/碩士(2018年)

https://doi.org/10.6840/cycu201800728

摘要

本論文提出影像對比度增強之硬體導向演算法，用來實現即時影像對比度增強積體電路實現。此演算法的核心為權重濾波器並隨著圖像中不同區塊選擇出最合適的亮度值，在分析這些亮度值之後，決定減少或提高圖像像素點的亮度值。本論文所提出的演算法開發將原本由整張圖像做運算的方法改為基於區塊的方式做運算，用於提高圖像品質，並利用圖像中各區域不同像素點的亮度值，來調整每塊區塊中像素點減少或提升的亮度值，以提升圖像的對比度。根據模擬結果，與先前的文獻做比較，本論文平均DE值提高了1%，平均CEF值提高了8.5%。在硬體方面，本論文所提出的即時影像對比度增強積體電路設計採用台積電0.18微米CMOS製程用於VLSI的實現，此方法的操作頻率在201 MHz時，邏輯閘個數為6028個，晶片面積為75,347 μm^2。

關鍵字

影像對比度增強 ； 影像對比度增強演算法 ； 影像對比度增強晶片設計

並列摘要

In this thesis, an efficient hardware-oriented contrast enhancement algorithm is proposed. The proposed algorithm is based on the weighted filter and calculates the brightness values according to the adjustment of the image. After analyzing these brightness values, it is decided to reduce or increase the brightness values of the points. In order to improve the quality of the image, the algorithm was developed by a block-based method rather than a frame-based one. The proposed algorithm uses the different brightness values of each area in the image to adjust the brightness value of the pixel reduction or lifting point in each block to improve the contrast of the image. According to the simulation results, compared with the previous algorithms, this work not only improved the average of DE by 1%, but also increased the average of CEF by 8.5%. An electronic design automation tool called Synopsys Design Vision was used for chip realization. This design was implemented by using TSMC 0.18 μm CMOS cell library. The results in this thesis represent that the gate counts is 6,028. The frequency is 201-MHZ, and the power is 17.47-mW.

並列關鍵字

Contrast Enhancement ； Contrast Enhancement Algorithm ； Contrast Enhancement Chip Design

參考文獻

[1] https://tberg.dk/post/determining-dominant-colors/

[2] R. C. Gonzalez and R. E. Woods, Digital Image Processing, Prentice-Hall, New Jersey, 2002.

[3] https://thilinasameera.wordpress.com/2011/03/23/contrast-stretching/

[4] C.-T. Shen and W.-L. Hwang, “Color image enhancement using retinex with robust envelope,” in Proc. 16th IEEE Int. Conf. Image Process., 2009, pp. 3141–3144.

[5] T. Arici, S. Dikbas, and Y. Altunbasak, “A histogram modification framework and its application for image contrast enhancement,” IEEE Trans. Image Process., vol. 18, no. 9, pp. 1921–1935, Sep. 2009.