PURPOSE A better understanding of photometry in laparoscopic images can increase the reliability of computer-assisted surgery applications. Photometry requires modelling illumination, tissue reflectance and camera response. There exists a large variety of light models, but no systematic and reproducible evaluation. We present a review of light models in laparoscopic surgery, a unified calibration approach, an evaluation methodology, and a practical use of photometry. METHOD We use images of a calibration checkerboard to calibrate the light models. We then use these models in a proposed dense stereo algorithm exploiting the shading and simultaneously extracting the tissue albedo, which we call dense shading stereo. The approach works with a broad range of light models, giving us a way to test their respective merits. RESULTS We show that overly complex light models are usually not needed and that the light source position must be calibrated. We also show that dense shading stereo outperforms existing methods, in terms of both geometric and photometric errors, and achieves sub-millimeter accuracy. CONCLUSION This work demonstrates the importance of careful light modelling and calibration for computer-assisted surgical applications. It gives guidelines on choosing the best performing light model.

中文翻译：

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腹腔镜中的光建模和校准。

目的更好地了解腹腔镜图像中的光度可以提高计算机辅助手术应用的可靠性。测光法需要建模照明，组织反射率和相机响应。存在各种各样的光照模型，但是没有系统且可重复的评估。我们目前对腹腔镜手术中的光模型，统一的校准方法，评估方法以及光度学的实际应用进行了综述。方法我们使用校准棋盘的图像来校准灯光模型。然后，我们在提议的密集立体算法中使用这些模型，该算法利用阴影并同时提取组织反照率，我们将其称为密集阴影立体。该方法适用于广泛的光照模型，为我们提供了一种测试它们各自优点的方法。结果我们表明，通常不需要过于复杂的光照模型，并且必须校准光源位置。我们还表明，就几何和光度误差而言，密集的阴影立体效果优于现有方法，并且可以达到亚毫米级的精度。结论这项工作证明了在计算机辅助手术应用中进行仔细的光建模和校准的重要性。它为选择最佳性能的光源模型提供了指导。结论这项工作证明了在计算机辅助手术应用中进行仔细的光建模和校准的重要性。它为选择最佳性能的光源模型提供了指导。结论这项工作证明了谨慎的光建模和校准对于计算机辅助手术应用的重要性。它为选择最佳性能的光源模型提供了指导。