可见光成像通信(OCC)是利用手机摄像头的卷帘快门工作方式拍摄快速闪烁的发光二极管(LED),接收明暗相隔的条纹图像,并通过对该图像进行解码恢复,实现数据通信的一种新兴的无线光通信技术。然而数据传输过程中出现的灰度值波动会影响通信过程中的误码率(BER)、传输距离和数据速率。提出了一种新型的OCC信号解调方案。利用基于膨胀腐蚀的自适应图像增强算法消除灰度值整体波动,利用膨胀算法消除灰度值局部波动,从整体和局部两个方面综合处理,最大程度上消除灰度值波动,提高判决的准确性,从而提高系统的通信性能。为验证所提方案的性能,评估了该方案在不同传输距离和数据速率环境下的BER。实验结果表明,所提方案的平均误码率较传统信号解调算法低两个数量级。

Total green leaf area (GLA) is an important trait for agronomic studies. However, existing methods for estimating the GLA of individual rice plants are destructive and labor-intensive. A nondestructive method for estimating the total GLA of individual rice plants based on multiangle color images is presented. Using projected areas of the plant in images, linear, quadratic, exponential and power regression models for estimating total GLA were evaluated. Tests demonstrated that the side-view projected area had a stronger relationship with the actual total leaf area than the top-projected area. And power models fit better than other models. In addition, the use of multiple side-view images was an efficient method for reducing the estimation error. The inclusion of the top-view projected area as a second predictor provided only a slight improvement of the total leaf area estimation. When the projected areas from multi-angle images were used, the estimated leaf area (ELA) using the power model and the actual leaf area had a high correlation coefficient (R2 > 0:98), and the mean absolute percentage error (MAPE) was about 6%. The method was capable of estimating the total leaf area in a nondestructive, accurate and efficient manner, and it may be used for monitoring rice plant growth.

采用波长为1 315 nm的连续波化学氧碘激光对某型摄像机进行了辐照实验，研究了可见光CCD成像系统在响应波段外红外激光辐照下的硬损伤效应。开展了光学系统变光圈尺寸下的激光辐照实验，发现当辐照水平一定的情况下，光圈尺寸越小，光学系统越难发生硬损伤，并解释了该现象的成因；测量到光圈尺寸最大、最小两种状态下的光学系统硬损伤功率阈值分别为几十W、几百W；得到CCD的激光损伤阈值为5.5×104 W/cm2；结合相机输出的视频图像与显微镜拍到的被损感光器件实物照片分析了硬损伤机理。