Matwyschuk Alexis
Appl Opt. 2014 Sep 20;53(27):6317-23. doi: 10.1364/AO.53.006317.
After the demonstration of the occurrence of visual artifacts with an active imaging system in burst mode in a previous paper, the analysis of this phenomenon was realized. A visual artifact resulting from a remote zone in the scene can appear in the image of the real visualized zone when the duty cycle of laser pulses is close to 50%, as in the burst mode. Therefore, the elements of this remote zone will create confusion in the image, with erroneous estimated distances. These misinterpretations can be very embarrassing to those attempting to determine the distance of a target in the scene. From the modeling realized and validated in the previous paper, the behavior of the visual artifact was analyzed with two types of burst mode used in active imaging, the duration of the laser pulse being identical to the duration of the temporal aperture of the imager. In the first mode, the width of the visualized zone is set, depending on the distance. The second mode increases the width of the visualized zone so that the foreground of the zone is constantly visible. The results showed that the distance of the visual artifacts in variable mode increased much more quickly than the distance in fixed mode. In both modes, the most intense visual artifacts appear when the range of the visualized zone remains within the first kilometer. When this range is very short, the illuminance of the visual artifact in fixed mode is much more intense than the illuminance in variable mode. On the other hand, for long distances, the illuminance of the visual artifact in variable mode is greater than the illuminance in fixed mode, but decreases quickly beyond a certain distance, making it insignificant.
在先前一篇论文中展示了主动成像系统在突发模式下出现视觉伪像的情况后，对这一现象进行了分析。当激光脉冲的占空比接近50%时，如在突发模式中，场景中远程区域产生的视觉伪像可能会出现在实际可视化区域的图像中。因此，这个远程区域的元素会在图像中造成混淆，导致距离估计错误。对于那些试图确定场景中目标距离的人来说，这些错误解释可能会非常棘手。根据先前论文中实现并验证的模型，利用主动成像中使用的两种突发模式对视觉伪像的行为进行了分析，激光脉冲的持续时间与成像器的时间孔径持续时间相同。在第一种模式下，可视化区域的宽度根据距离进行设置。第二种模式增加了可视化区域的宽度，以便该区域的前景始终可见。结果表明，可变模式下视觉伪像的距离比固定模式下的距离增加得更快。在两种模式下，当可视化区域的范围保持在第一公里内时，视觉伪像最为强烈。当这个范围非常短时，固定模式下视觉伪像的照度比可变模式下的照度强烈得多。另一方面，对于长距离，可变模式下视觉伪像的照度大于固定模式下的照度，但在超过一定距离后会迅速降低，变得微不足道。
