Forest inventorying is time-consuming and expensive. Recent research involving photogrammetry promises to reduce the cost of inventorying. Existing photogrammetry methods require substantial data-processing time, however. Our aim was to reduce data-acquisition and processing times while obtaining relatively accurate diameter estimates compared to manual and other digital measurements. We developed an algorithm to identify the ground and measure diameter at breast height (dbh) or any height along a stem from the recorded video footage of trees taken with a stereo camera. Footage acquisition time, dbh root mean square error, and mean absolute error were used as comparison metrics with other methods. The time to perform three recordings for 40 trees was about 30 minutes. We recorded data at 1 m, 3 m, and 5 m from the trunk, and our dbh root mean square errors were 1.28 cm (0.50 in.), 1.47 cm (0.58 in.), and 2.57 cm (1.01 in.), respectively, using manual measures as the control. This terrestrial stereoscopic photogrammetric method is much more efficient computationally than popular terrestrial structure-from-motion photogrammetry and substantially lowers time, costs, and complexity for data acquisition and processing compared with terrestrial laser scanning.

中文翻译：

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地面立体摄影测量法的快速树径计算

森林盘查既费时又昂贵。涉及摄影测量的最新研究有望降低库存成本。然而，现有的摄影测量方法需要大量的数据处理时间。我们的目标是减少数据采集和处理时间，同时获得与手动和其他数字测量相比相对准确的直径估计。我们开发了一种算法，可以识别地面并测量胸部高度（dbh）或沿茎的任何高度的直径，该直径来自用立体摄像机拍摄的树木的录制视频镜头。素材采集时间，dbh均方根误差和平均绝对误差用作与其他方法的比较指标。对40棵树进行三次录音的时间约为30分钟。我们记录了距离树干1 m，3 m和5 m的数据，使用手动测量作为对照，我们的dbh均方根误差分别为1.28厘米（0.50英寸），1.47厘米（0.58英寸）和2.57厘米（1.01英寸）。这种地面立体摄影测量方法比流行的地面从运动摄影结构测量方法具有更高的计算效率，并且与地面激光扫描相比，大大降低了数据采集和处理的时间，成本和复杂性。