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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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🏛️國立陽明交通大學機構典藏

Author: search.filters.author.Cheng, Chu-MingHas files: No

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    Accessing Refractive Errors via Eccentric Infrared Photorefraction Based on Deep Learning
    (2019-01-01)
    Yang, Chia-Chi
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    Su, Jian-Jia
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    Li, Jie-En
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    Zhu, Zhi-Yu
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    Tseng, Jin-Shing
    Eccentric infrared photorefraction is an attractive vision screening method which is widely used for uncooperative subjects, such as infants and toddlers. Unlike conventional slope-based photorefraction, a deep neural network is used to predict refractive error in this study. Total 1216 ocular image were collected by a homemade photorefraction device, whose corresponding refractive error was measured by a commercial autorefractor device, to create a series of dataset for our deep neural network. The mean squared error of the preliminary result is +/- 0.9 diopter, which indicates its feasibility and can be improved with bigger database.
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    Design of a dual-f-number illumination system and its application to DMD (TM) projection displays
    (2006-09-01)
    Cheng, Chu-Ming
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    Chern, Jyh-Long
    ;
    光電工程學系
    ;
    Department of Photonics
    A dual-f/# optical system is evaluated and considered for illumination. Etendue theory has been employed to increase the optical throughput and collection efficiency. A classical Cooke triplet with a dual f/# is included for illustration. As a demonstration of the potential application to projection displays, an elliptically shaped illumination-pupil system is proposed to increase the optical collection efficiency in the DMD(TM) (Digital Micromirror Device(TM))-based projection system. With a dual-f/# configuration, this design can eliminate the f/2.4 constraint that was caused by the light-steering action of the narrow +/- 12 degrees tilt angles on the DMD(TM). The percentage of increase in the optical collection efficiency is 6.2% in the dual f/2.0 x f/2.4 optical projection system by using ray-tracing simulation. This method enables a lower than f/2.4 optical design with a high brightness and an adequate contrast ratio in the DMD(TM)-based projectors.
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    Optical transfer functions for specific-shaped apertures generated by illumination with a rectangular light pipe
    (2006-12-01)
    Cheng, Chu-Ming
    ;
    Chern, Jyh-Long
    ;
    光電工程學系
    ;
    Department of Photonics
    We investigated the pupil functions of specific-shaped apertures generated by Lambertian illumination with a rectangular light pipe to derive the corresponding optical transfer functions (OTFs) in aberration-free and defocused optical systems. The semianalytical results indicate that the curves of the OTF of the optical system vary with the form of the shaped apertures that are generated by illumination with different geometric structures of light pipes and light sources. It was found that the OTF values of even-peak frequencies decrease when the Lambertian light source decreases. If there are a total of n X n individual apertures within a pupil, then n near-periodical peaks will appear on the OTF curve. It is evident that the values of the OTF remain almost unchanged even when the lengths of the light pipes are different. Furthermore, the geometric structure of the light pipe does not affect the resolution limit of the optical system, and under the condition of a larger defocused coefficient omega(20), the results of the defocused system can coincide with those of the aberration-free systems. (c) 2006 Optical Society of America.