QR code is a 2D matrix barcode widely used for product tracking, identification, document management and general marketing. Recently, there have been various attempts to utilize QR codes in 3D manufacturing by carving QR codes on the surface of the printed 3D shape. Nevertheless, significant shape editing and modulation may be required to allow readability of the embedded 3D‐QR‐codes with good decoding accuracy. In this paper, we introduce a novel QR code 3D fabrication framework aimed at unobtrusive embedding of 3D‐QR‐codes in the shape hence introducing minimal shape modulation. Essentially, our method computes bi‐directional carvings in the 3D shape surface to obtain the black‐and‐white QR pattern. By using a directional light source, the black‐and‐white QR pattern emerges as lighted and shadow casted blocks on the shape respectively. To account for minimal modulation and elusiveness, we optimize the QR code carving w.r.t. shape geometry, visual disparity and light source position. Our technique employs a simulation of lighting phenomena through carved modules on the shape to ensure adequate contrast of the printed 3D‐QR‐code.

中文翻译：

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具有定向光的可制造不显眼的 3D-QR 码

二维码是一种二维矩阵条码，广泛用于产品跟踪、识别、文档管理和一般营销。最近，通过在打印的 3D 形状的表面上雕刻 QR 码，已经有各种尝试在 3D 制造中利用 QR 码。然而，可能需要进行大量的形状编辑和调制，以允许具有良好解码精度的嵌入式 3D-QR 码的可读性。在本文中，我们介绍了一种新颖的 QR 码 3D 制造框架，旨在将 3D QR 码不显眼地嵌入到形状中，从而引入最小的形状调制。本质上，我们的方法计算 3D 形状表面中的双向雕刻以获得黑白 QR 图案。通过使用定向光源，黑白 QR 图案分别以光照和阴影投射块的形式出现在形状上。考虑到最小的调制和难以捉摸，我们优化了二维码雕刻形状几何、视觉差异和光源位置。我们的技术通过在形状上雕刻模块来模拟照明现象，以确保打印的 3D 二维码具有足够的对比度。