长期监测计划,以评估气候驱动的潮水冰川变化,阿拉斯加海豹(Phocavitulina)的重要栖息地,主要是由昂贵的,来自固定翼飞机的依赖于天气的航测。无人机系统(UAS)可以是一个替代的成本有效的解决方案,用于收集图像数据进行量化,监视器,管理这些栖息地。然而,ThereisapaucityofinformationrelatedtotheaccuracyofusingimagecollectedbyUASforpurposeofmeasuringfloatingicebergs.我们评估了使用内置20百万像素(MP)相机的UAS以及消费级数字16MP相机捕获浮动和固定冰山图像的准确性,以收集垂直高度测量值。捕获了模拟冰山(长方体泡沫盒)“Cb”(n=5)和接地或浮动的真实冰山(n=5)的图像(n=869)。获得的平均误差比率小于10%,并且通过比较从UAS捕获的图像获得的Cb高度的平均计算测量值与这些Cb的物理测量高度而得出。接地冰山(n=4)和一个浮动冰山的高度测量的平均误差比也小于10%。在6-25米的物像距离范围内,摄像机拍摄的图像适合于准确计算漂浮和接地物体的高度,anddriftoruntrolledmovementoftheUAScausedbywindortemporarylossofGPSdidnotappeartohaveanysignificanteffectsonmeasurementerror.我们的研究提供了大量证据,证明与使用UAS捕获的图像来测量位于水和陆地表面的结构尺寸相关的高精度。最终,对海豹使用的冰川冰的准确调查将提高我们对栖息地减少在解释不同潮水冰川之间种群变化方面的作用的理解。
Long-term monitoring programs to evaluate climate-driven changes to tidewater glaciers, an important habitat for harbor seals (Phoca vitulina) in Alaska, are primarily carried out by costly, weather-dependent aerial surveys from fixed-winged aircraft. Unmanned aerial systems (UAS) can be an alternative cost-effective solution for gathering image data to quantify, monitor, and manage these habitats. However, there is a paucity of information related to the accuracy of using imagery collected by UAS for purposes of measuring floating
icebergs. We evaluated the accuracy of using a UAS with a built-in 20 megapixel (MP) camera as well as a consumer-grade digital 16 MP camera to capture images of floating and stationary
icebergs for the purpose of collecting vertical height measurements. Images (n=869) were captured of simulated
icebergs (Cuboidal foam boxes) \"Cb\" (n=5) and real
icebergs (n=5) that were either grounded or floating. The mean error ratios obtained were less than 10% and derived by comparing the mean calculated measurements of heights of Cb obtained from images captured by UAS with the physically measured heights of these Cb. The mean error ratio for height measurements of grounded
icebergs (n=4) and one floating iceberg was also less than 10%. Within an object-image distance range of 6-25 m, the cameras captured images that were suitable to accurately calculate the heights of floating and grounded objects, and drift or uncontrolled movement of the UAS caused by wind or temporary loss of GPS did not appear to have any significant effects on measurement error. Our study provides substantial evidence of the high accuracy associated with using images captured by UAS for measuring dimensions of structures positioned on water and land surfaces. Ultimately, accurate surveys of glacial ice used by harbor seals will improve our understanding of the role of decreasing habitat in explaining population variability between different tidewater glaciers.