Author Affiliations
Abstract
State Key Laboratory of Digital Manufacturing Equipment and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
This Letter presents a novel approach to enhance the fringe contrast (visibility) in a digital off-axis hologram digitally, which can save several adjustment procedures. In the approach, we train a pair of coupled dictionaries from a low fringe contrast hologram and a high one of the same specimen, use the dictionaries to sparse code the input hologram, and finally output a higher fringe contrast hologram. The sparse representation shows good adaptability on holograms. The experimental results demonstrate the benefit of low noise in a three-dimensional profile and prove the effectiveness of the approach.
090.1995 Digital holography 100.2980 Image enhancement Chinese Optics Letters
2016, 14(6): 060901
1 复旦大学环境科学与工程系, 上海 200433
2 上海烟草(集团)公司技术中心, 上海 200082
利用差分光学吸收光谱(DOAS)仪对不同品牌卷烟主流烟气中的NO2进行连续、实时、在线测量,使用RM200型转盘式20孔道吸烟机,一次将20只卷烟顺序输送到吸烟转盘上,间隔3 s依次点火,并将卷烟烟气通入与之直接相连的总光程为31.5 m的怀特池,利用差分光学吸收光谱技术,可在6～7 min之内完成对整只卷烟的逐口测量,提高了测量结果的时间分辨率。抽吸开始时,怀特池气压被抽到5.2×104 Pa,所有卷烟完成测量时,气压恢复到1.03×105 Pa;抽吸结束后,怀特池中NO2的浓度在0.89 mg/m3和1.54 mg/m3之间。比较不同品牌的卷烟,主流烟气中NO2浓度有明显差别,特别是混和型卷烟比烤烟型高83％,该技术对卷烟烟气成分的快速检测提供了一种简便的方法。
光谱学 光谱分析 卷烟主流烟气 差分光学吸收光谱仪 二氧化氮 快速检测
