Schwartz Broderick S, Bell Tyler
Appl Opt. 2022 Feb 20;61(6):1559-1568. doi: 10.1364/AO.445800.
The use of three-dimensional (3D) range geometry is expanding across a variety of disciplines ranging from medicine to the visual arts. A large amount of information is available in 3D range geometry, causing some applications to be limited in their ability to effectively store or transmit captured data. To help alleviate this constraint, a variety of 3D range data compression techniques have been proposed. One method, multiwavelength depth (MWD) encoding, smoothly encodes 3D range geometry into the three color channels of a 2D RGB image. To the best of our knowledge, we present a novel compression enhancement to further reduce file sizes that employs image downsampling, MWD encoding, and lossless (e.g., PNG) or lossy (e.g., JPEG) compression. Image upsampling is used to return downsampled encodings to their original resolution from which the 3D information is then decoded. The proposed method is robust to various scales of downsampling and levels of lossy compression. For example, when this method was applied with 50% downsampling and JPEG 85 to an encoding of a 3D face scan, a compression ratio of 68.85:1 versus the raw data was achieved with a global RMS reconstruction accuracy of 98.77%. Experimental results demonstrate that the proposed method can provide substantial file size savings at minimal reduction in overall reconstruction accuracy.
三维（3D）距离几何的应用正在从医学到视觉艺术等各种学科中不断扩展。3D距离几何中存在大量信息，这使得一些应用在有效存储或传输捕获的数据方面能力有限。为了缓解这一限制，人们提出了各种3D距离数据压缩技术。一种方法是多波长深度（MWD）编码，它将3D距离几何平滑地编码到二维RGB图像的三个颜色通道中。据我们所知，我们提出了一种新颖的压缩增强方法，通过图像下采样、MWD编码以及无损（如PNG）或有损（如JPEG）压缩来进一步减小文件大小。图像上采样用于将下采样后的编码恢复到其原始分辨率，然后从中解码3D信息。所提出的方法对于各种下采样比例和有损压缩级别都具有鲁棒性。例如，当该方法以50%的下采样率和JPEG 85应用于3D面部扫描的编码时，与原始数据相比实现了68.85:1的压缩比，全局均方根重建精度达到98.77%。实验结果表明，所提出的方法能够在整体重建精度降低最小的情况下大幅节省文件大小。
