Reconstruction of 3D surface irradiance distribution using multiple views captured by charged coupled device(CCD)camera is the basis of solving the light source in bioluminescence tomography(BLT).A simple and convenient mapping technique based on the pin-hole imaging model and Lambert′s cosine law was presented to establish the relationship between gray levels and irradiance intensities.Compared with previous integrating sphere camera calibration used in BLT,the proposed method can effectively avoid heavy burden of simulation experiment to obtain the corresponding relationship of gray levels and irradiance intensities.The accuracy and feasibility of the proposed method are validated with no more than 1mm location error by different types of phantom experiments.The mapping approach is also applicable to other noncontact optical imaging system.
随着3D电视显示技术的普及,观看3D电视产生的大脑疲劳问题越来越受到关注。初步探讨长时间观看3D电视导致大脑疲劳的机理。采集20名受试者(男女比例1∶1)分别连续观看1 h 3D或2D影片前后各5 min的脑电信号,并使用主观疲劳问卷量表评估被试观看前后的疲劳状况。利用希尔伯特变换的方法,分析脑电各通道信号之间的同步性,探讨脑电信号的空间特性,并对观看2D/3D电视前后脑电信号进行溯源分析。主观疲劳问卷量表评估发现,长时间观看3D电视大脑会出现显著疲劳症状(P<0.01)。脑电信号溯源分析发现,长时间观看2D/3D电视后大部分脑区各频段电流源密度有所减小,但统计结果无显著性差异(P>0.05)。然而,观看3D电视后,枕叶在β2频段电流源密度显著增强(P<0.01),且观看3D电视后枕叶显著增强部分与主观疲劳因子显著相关(P<0.01)。观看3D电视后与观看2D电视后相比,缘上回(BA40),枕叶(BA18,BA19)和中央后回(BA3)等与空间视觉信息处理相关区域在β1频段电流密度分布显著增强(P<0.05),处于相对较活跃状态。因此,研究结果可以推测,长时间观看2D/3D电视后大脑会出现疲劳症状,相比观看2D电视,观看3D电视会加大枕叶和缘上回等局部脑区的处理负担,这可能是长时间观看3D电视更容易产生脑疲劳的原因。
