光子计数激光雷达技术具有极高的探测灵敏度与时间分辨率,是极端条件下高精度目标信息获取的重要手段.由于该技术通过探测单光子级的回波能量实现对目标信息的三维重建,因此极易受噪声干扰,导致成像质量严重降低.基于高速电子门控的距...光子计数激光雷达技术具有极高的探测灵敏度与时间分辨率,是极端条件下高精度目标信息获取的重要手段.由于该技术通过探测单光子级的回波能量实现对目标信息的三维重建,因此极易受噪声干扰,导致成像质量严重降低.基于高速电子门控的距离选通技术虽然可以有效抑制噪声,但存在参数设计依靠经验、目标检测区间窄等问题.本文提出一种在宽目标检测区间条件下的目标信息提取及三维重建方法,首先通过对三维回波信息的获取机理及其概率模型进行分析,获取目标信息分布范围并通过算法门控提取有效信息;再采用高效的图像重建算法进一步提升三维重建的质量,从而具有比基于纯硬件的去噪方法更强的抑噪能力.实验结果显示,在平均像素光子数仅为3.020,且信号噪声比仅为0.106的极端条件下,本文提出的目标信息提取方法可将信号噪声比提升19.330倍;再配合高效的图像重建算法,距离图像的重建信噪比相比于传统的互相关算法提升了33.520 d B,大幅提升了强噪声环境下高精度目标信息获取的能力.展开更多
Conventional color-printing systems often use inks of three hues, such as CMY, CMYK and CMYKLcLm, but in order to obtain more realistic color reproductions, the ink set of more than three hues has been adopted by some...Conventional color-printing systems often use inks of three hues, such as CMY, CMYK and CMYKLcLm, but in order to obtain more realistic color reproductions, the ink set of more than three hues has been adopted by some color-printing systems. It is difficult, however, to model the composed color with the multiple inks when the number of the output ink hues exceeds three due to the none-unique mapping between the color spaces of the CIE Lab and the multi-color printing device. In this paper, we propose a fine color-printing method for multi-color printing device with the ink set of more than three hues. The proposed approach has good color expression ability and provides fine control of the printed color. By dividing the output color space into several subspaces, our method allows one-to-one mapping between the standard color space and the multi-color output color space. It has been proved effective when applied to the digital inkjet printer—Mutoh8000.展开更多
目的探讨AO微型锁定髁钢板治疗第五掌骨颈骨折的临床疗效。方法对本院2013年1月至2016年1月收治的37例有明显背侧成角畸形、旋转不稳定的第五掌骨颈骨折病人进行回顾性研究,均采用AO微型锁定髁钢板进行有限切开复位、钢板桥接内固定治疗...目的探讨AO微型锁定髁钢板治疗第五掌骨颈骨折的临床疗效。方法对本院2013年1月至2016年1月收治的37例有明显背侧成角畸形、旋转不稳定的第五掌骨颈骨折病人进行回顾性研究,均采用AO微型锁定髁钢板进行有限切开复位、钢板桥接内固定治疗,术后早期进行康复功能锻炼。通过术前、术后、随访中的X线片,评判骨折复位及畸形纠正情况;测量第五掌骨头干角;根据中华医学会手外科学会上肢部分功能评定使用标准中的手指总主动活动度(total active motion,TAM)测定法评价术后的手功能恢复情况。结果术后病人一期愈合,37例均得到随访,随访时间为6~15个月,术后无骨折不愈合及延迟愈合,无钢板突出、螺钉松动及伤口感染等并发症;术后头干角为16.7°±2.3°,与术前的58.2°±15.4°比较,差异有统计学意义(P<0.05);术后TAM为80.3°±9.2°,优29例,良6例,优良率为94.6%。结论对于第五掌骨颈骨折,应用AO微型锁定髁钢板可获得良好的临床效果,具有手术操作简单、创伤小、无明显术后并发症等特点,可作为一种治疗第五掌骨颈骨折的有效方法。展开更多
文摘光子计数激光雷达技术具有极高的探测灵敏度与时间分辨率,是极端条件下高精度目标信息获取的重要手段.由于该技术通过探测单光子级的回波能量实现对目标信息的三维重建,因此极易受噪声干扰,导致成像质量严重降低.基于高速电子门控的距离选通技术虽然可以有效抑制噪声,但存在参数设计依靠经验、目标检测区间窄等问题.本文提出一种在宽目标检测区间条件下的目标信息提取及三维重建方法,首先通过对三维回波信息的获取机理及其概率模型进行分析,获取目标信息分布范围并通过算法门控提取有效信息;再采用高效的图像重建算法进一步提升三维重建的质量,从而具有比基于纯硬件的去噪方法更强的抑噪能力.实验结果显示,在平均像素光子数仅为3.020,且信号噪声比仅为0.106的极端条件下,本文提出的目标信息提取方法可将信号噪声比提升19.330倍;再配合高效的图像重建算法,距离图像的重建信噪比相比于传统的互相关算法提升了33.520 d B,大幅提升了强噪声环境下高精度目标信息获取的能力.
基金Project (No. M603034) supported by the Natural Science Foundationof Zhejiang Province, China
文摘Conventional color-printing systems often use inks of three hues, such as CMY, CMYK and CMYKLcLm, but in order to obtain more realistic color reproductions, the ink set of more than three hues has been adopted by some color-printing systems. It is difficult, however, to model the composed color with the multiple inks when the number of the output ink hues exceeds three due to the none-unique mapping between the color spaces of the CIE Lab and the multi-color printing device. In this paper, we propose a fine color-printing method for multi-color printing device with the ink set of more than three hues. The proposed approach has good color expression ability and provides fine control of the printed color. By dividing the output color space into several subspaces, our method allows one-to-one mapping between the standard color space and the multi-color output color space. It has been proved effective when applied to the digital inkjet printer—Mutoh8000.
文摘目的探讨AO微型锁定髁钢板治疗第五掌骨颈骨折的临床疗效。方法对本院2013年1月至2016年1月收治的37例有明显背侧成角畸形、旋转不稳定的第五掌骨颈骨折病人进行回顾性研究,均采用AO微型锁定髁钢板进行有限切开复位、钢板桥接内固定治疗,术后早期进行康复功能锻炼。通过术前、术后、随访中的X线片,评判骨折复位及畸形纠正情况;测量第五掌骨头干角;根据中华医学会手外科学会上肢部分功能评定使用标准中的手指总主动活动度(total active motion,TAM)测定法评价术后的手功能恢复情况。结果术后病人一期愈合,37例均得到随访,随访时间为6~15个月,术后无骨折不愈合及延迟愈合,无钢板突出、螺钉松动及伤口感染等并发症;术后头干角为16.7°±2.3°,与术前的58.2°±15.4°比较,差异有统计学意义(P<0.05);术后TAM为80.3°±9.2°,优29例,良6例,优良率为94.6%。结论对于第五掌骨颈骨折,应用AO微型锁定髁钢板可获得良好的临床效果,具有手术操作简单、创伤小、无明显术后并发症等特点,可作为一种治疗第五掌骨颈骨折的有效方法。
