Wing images used for testing new methods for estimating the total wing area of birds

Images of extended wing preparations of 112 specimens representing 40 avian families were used for testing new methods for estimating the total wing area of birds.

Methods
Spread wings photographed at the ROM were placed on white paper on a copy stand with a Nikon Z50 mirrorless camera mounted directly above the wing. An L-shaped ruler was placed next to the wing to provide the scale. Two Godox LEDP260C Bi-Color LED light panels on tripods were set at 100% brightness and 5000K color temperature and placed on either side of the camera to minimize shadows. Large wings were photographed in the ROM’s photo studio. Wings at LSU were photographed using a hand-held camera and a digital or manual leveler to ensure the camera was directly above the wing. To reduce measurer error, photographs were taken and digitally measured only by H.F. and M.S. 
Processed images were obtained using ImageJ v.1.53 (U.S. National Institutes of Health, Bethesda, Maryland). We set the scale using the scale ruler in the image and used the “Threshold” tool to transform the photo into a binary (black and white) image, sometimes followed by the “Fill Holes” option. Most images were further edited manually using the “Brush” tool to fill small border gaps in broken or disarranged feather vanes, or to fill marginal white spots not distinguished from the background by the thresholding tool. Finally, the “Eraser” tool was used to delete anomalies due to disarranged cover feathers, usually near the shoulder area, and to create a straight proximal border that would represent the root chord (parallel to the axis of the body and perpendicular to the wing leading edge).

本研究采用代表40个鸟类科的112份标本的展翅标本图像，以测试鸟类翼总面积的估算新方法。
方法
在皇家安大略博物馆（ROM）拍摄的展翅标本，被放置于复印架上的白纸之上，采用尼康Z50无反相机垂直正对翼面拍摄。于翼旁放置L形标尺以提供比例尺。在三脚架上安装两台神牛LEDP260C双色温LED补光灯，设置为100%亮度与5000K色温，分别置于相机两侧以尽量减少阴影。大型翼标本在ROM的摄影棚内拍摄。路易斯安那州立大学（LSU）的翼标本则采用手持相机配合数字或手动水平仪，确保相机垂直正对翼面进行拍摄。为减小测量误差，仅由H.F.与M.S.二人完成图像拍摄与数字化测量工作。
处理后的图像通过ImageJ v.1.53（美国马里兰州贝塞斯达市美国国立卫生研究院开发）获取。首先利用图像中的标尺设置比例尺，随后通过“阈值（Threshold）”工具将照片转换为二值（黑白）图像，部分图像还会执行“填充孔洞（Fill Holes）”操作。大多数图像还需使用“画笔（Brush）”工具进行手动编辑，以填补破损或杂乱的羽枝边缘缝隙，或填补阈值工具无法与背景区分开的边缘白斑。最后，使用“橡皮擦（Eraser）”工具清除因杂乱覆羽（通常位于肩部区域）产生的异常区域，并绘制平直的近端边界以代表翼根弦长（该边界平行于躯体轴线，且垂直于翼前缘）。