雙視域式立體顯示器影像品質研究

Abstract

近年來可3D相容顯示器被大量推廣使用，立體顯示器的影像品質評定也益顯重要。除了眼鏡式立體顯示器技術已逐漸成熟，裸眼式立體顯示器的開發也逐漸受到產業界及學術界的重視，被視為下一代立體顯示器主流技術。目前立體顯示器的種類繁多，並隨著不同市場與應用的興起，一致性的影像品質檢定標準更形重要。裸眼式立體顯示中的視差屏障式立體顯示器具有輕薄、易於2D/3D切換等優點已經被廣泛應用於電腦螢幕、手機、數位相框等，所以是本研究的主要探討對象。 立體顯示器的品質檢測是整個產業成功的基石。除了關係使用者的觀看舒適度，更是立體顯示器設計者、人因測試者與影像處理開發人員憑藉的標竿。而這些問題重要性也已經廣泛受到重視。裸眼式立體顯示器的影像品質與觀賞者與顯示器之間相對的距離與角度都有很大關係，所以最佳觀測點、最佳觀測距離及觀者在最佳觀測點附近能夠移動範圍的觀賞視域都是重要顯示系統參數，以上參數目前已經有許多研究報導，但是更深入且基礎的問題還需要更多的研究作確認。顯示器的設計、製作到實驗驗證間的相互聯結也需要更進一步的研究來證實。本研究提出基於幾何光學及光線追跡的新立體影像評價方式來評估觀賞視域，並加入實務上必須考量的玻璃折射率、影像干擾、均勻度等做綜合考量。 本研究主要是從基礎理論出來，並考量實際製作到作最後的量測、評價，提供有價值的參考依據給立體顯示器的設計者、人因測試者到量測技術、立體標準制定建立。

With the increasing usage of 3D compatible displays, the optical quality assessment of these displays is more and more important. Besides stereoscopic display, one of the amazing 3D displays is an auto-stereoscopic display without using extra glasses for the observers. Auto-stereoscopic display will definitely be the main stream of the 3D display market in the near future. Since two-view parallax-barrier type auto-stereoscopic displays have been applied in the handheld display market such as handheld game machines, digital photo frame, digital cameras and mobile phones for a while, we focus on this kind of auto-stereoscopic display in this study. 3D display quality assessment is the bedrock for the 3D display industry, so 3D display metrology is getting more and more important with rapidly growing 3D market. For the auto-stereoscopic display, the image quality for observers depends on both the viewing distance and viewing angle. Therefore, there are designated eye positions (DEPs) which are the best viewing positions for each eye at the viewing plane and OVD (optimal viewing distance) is proposed as a viewing distance providing the viewer with the optimal stereoscopic experience. Besides, a viewing zone (VZ), in which an observer is free to move and can still perceive good stereopsis, is another important issue for the auto-stereoscopic display. Although there have been lots of studies on VZ, deeper researches are still needed for further understanding. Thus this study proposes a novel evaluation method to describe VZ by a novel formula and discussing the affecting factors for VZ of the parallax barrier auto-stereoscopic display, such as the refraction index of panel glass, the system crosstalk, and the uniformity, by the geometric and the ray tracing methods, respectively. This study provides not only the evaluation metrics for crosstalk, DEPs, OVD and VZ of an auto-stereoscopic display in a very clear and coherent manner, but also relates the image quality assessment to the design parameters which will be a valuable reference to the auto-stereoscopic display metrology, display standard, 3D human factor studies, as well as system designers.