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標題: | 逆向全光場系統之研發:照明投影系統應用平台之設計及建置 Research and Development of Reverse Plenoptic System: Design and Construction of Illumination Projection System platform |
作者: | Kuan-Ming Chen 陳冠名 |
指導教授: | 李世光 |
關鍵字: | 全光場,光場,同軸光學,照明, Plenoptic,Light field,coaxial optic,illumination, |
出版年 : | 2015 |
學位: | 碩士 |
摘要: | 在現代,使用智慧型手機拍照越來越普及,在光源不足的情況下就需要補光燈的照明,傳統智慧型手機補光燈的設計範圍多固定在1.5公尺,而使用者進行拍攝時,許多時候不能夠站在待拍攝物固定距離前,因此補光範圍將超出拍攝區域,這些無效光照造成能量的虛耗,大量犧牲了手機電池的續航力。為解決上述問題,使補光燈能準確對拍攝物補光,本研究設計一補光系統,根據光場相機的第二代全光場系統結構,發展出一與全光場系統光路方向相反的逆向全光場系統,逆向全光場系統則是在影像感測元件周圍布置光源,每一光源前方有一微透鏡,光源發出的光線經由微透鏡與主透鏡回到物方,其補光範圍即拍照範圍。
本研究以CodeV模擬軟體來設計逆向全光場系統的光路結構,匯入其光路模型到另一個光學模擬軟體LightTools進行照明模擬,由於光源偏離光軸,在視野上有些微的差距,以定焦鏡頭模型模擬,影像感測元件周圍的光源造成的補光範圍會略大於尺寸為1/2.3”之影像感測元件的視野範圍。而使鏡頭變焦,系統仍維持其補光效果。本研究以鏡頭、球鏡、LED及影像感測元件搭建一逆向全光場模型。使鏡頭對焦在不同深度立體模型,及對不同深度的兩物體進行補光,由影像感測元件可以看到拍攝物體的補光照明結果,側拍鏡頭被用來解析被照明物體的補光範圍變化和因為LED置放於CMOS/CCD旁所造成的背景光雜訊。 本研究針對設計的逆向全光場系統,分別以模擬及實驗的方式驗證其補光的效果,兩者的補光範圍均大於影像感測元件的視野範圍,且隨著對焦位置不同而有補光範圍約略改變,但整體而言,仍具備針對不同放大與不同拍攝距離,補光區與拍照範圍幾乎重和的效果。 More and more people are using smart phone to take photographs in recent years. Fill flash light is needed when there is not sufficient external lighting for illumination. However, fill exposure lights of the smart phone camera are usually designed to aim at objects located 1.5 meters in front of the lens. Since photographers are not always taking photograph at that distance, the fill light region usually exceeds the intended exposure area. This ineffective illumination wasted the fill light and resulted in shorter operating time for smart phones. In order to deal with the drawbacks mentioned above and to make sure the fill illumination light located only on the region covers the intended photograph subjects, this thesis developed a new fill illumination system. This system, called reverse plenoptic system, is based on the configuration of Plenoptic 2.0 camera except that the illumination light travels along the opposite direction. In this system, light sources are placed around the CCD/CMOS sensor. Each and every of the light sources has a micro lens mounted in front of it. Light beam goes through the micro lens and the main lens and finally illuminates on the subject. The fill illuminated range was found to match the intended photographic region. The reverse plenoptic system module was simulated by an optical simulation package CodeV first to set up the lens layout. The fill illumination was then simulated by using another simulation software LightTools. With the deviation of the light source and the main optical axis, a small view difference between the fill illuminated region and the intended photographic area was discovered. In the case of fixed focus lens simulation case, the fill illuminated range of the system light source is slightly larger than the captured range of 1/2.3” frame size. The fill illuminated range changes while the main lens zoom in or zoom out. The reverse plenoptic system analyzed in this thesis was set up by using a camera lens, a micro lens, LED and a CMOS camera. Exposure experiments were pursued to illuminate intended photographic objects located at different distance and different zoom ratio. The fill illuminated subject was captured by using CMOS camera. The effect of the fill illuminated range changes with the focusing depth were observed by using the side camera so as to separate the effect of the fill illumination and the back light noise created by placing the LED so close to the CMOS. In summary, for the reverse plenoptic system proposed in this thesis, both the simulation and the experiments were performed. With our design, the illuminated region was found to be slightly larger than the intended photographic region. However, both the simulation and the experimental results confirm the intended the results, i.e., the fill illuminated region almost matches the intended photographic region for different zoom ratio with respect to objects located at different distances in front of the photographic lens. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/52852 |
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顯示於系所單位: | 應用力學研究所 |
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