一個實用的紅外線影像對比強化方法

Abstract

由於紅外線的影像格式通常為12位元或14位元，而在視覺的觀測上都是使用8位元的格式，因此需要作位元壓縮 (對比強化) 來將12或14位元轉成8位元。本論文係針對紅外線影像的特性，提出一個避免因紅外線強度分佈多的物體擠壓強度分佈少的物體時，所發生的影像擠壓現象，以及避免溫度擴散模糊的現象，同時亦能降低雜訊的方法。此方法乃為針對BOHP與HE位元壓縮方法的缺點所做的改良，除改善影像處理效果外，亦考慮可縮短計算時間的硬體設計，以確保能應用在即時系統上。

In general, infrared image formats are 12-bit or 14-bit. For visual inspection purposes, they are always converted to 8-bit video format. In this paper, characteristics of infrared image are investigated, and a method for format conversion that can avoid (1) destruction of image content due to intensity compression, (2) temperature diffusion effect, and (3) noise enhancement is proposed. This method can be regarded as an improvement over widely adopted BOHP and HE schemes. In addition to better image quality, real-time implementation issues are also considered.