In this paper, we introduce isophote curves on surfaces in Galilean 3-space. Apart from the general concept of isophotes, we split our studies into two cases to get the axis d of isophote curves lying on a surface such that d is an isotropic or a non-isotropic vector. We also give a method to compute isophote curves of surfaces of revolution. Subsequently, we show the relationship between isophote curves and slant (general) helices on surfaces of revolution obtained by revolving a curve by Euclidean rotations. Finally, we give some characterizations for isophote curves lying on surfaces of revolution.

中文翻译：

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关于伽利略空间中等渗线的几何

在本文中，我们介绍了Galilean 3空间中曲面上的等渗线。除了等渗线的一般概念之外，我们将研究分为两种情况，以使等渗线曲线的轴d位于表面上，使得d是各向同性或非各向同性的向量。我们还提供了一种计算旋转曲面的等视线曲线的方法。随后，我们展示了等密度线曲线与通过欧几里德旋转使曲线旋转而获得的旋转表面上的倾斜（一般）螺旋之间的关系。最后，我们给出了旋转表面上等腰线曲线的一些特征。