工业图像处理用光源的类型

If it gets too dark when reading, a lamp is the answer. If a piece of paper is printed with low contrast, it can be exposed to the sun for better readability. If a photographer wants to put something into perspective, he or she uses colored spotlights. What is useful in everyday life – the correct intensity and type of illumination – is also crucially important for machine vision, as natural lighting is often not available or insufficient or can also be unsuitable or obstructive depending on the application.

For this reason, illumination plays major role in the design of image processing systems. Type, color, and intensity have a major impact on what is visible of a test object and can therefore be captured by a camera or a vision sensor for evaluation. It follows that the purpose of correct illumination is to emphasize the characteristics of a test object in the best possible manner to allow the entire image processing system to function reliably.

Illumination is divided into incident light, dome light, dark field light, and back light. Based on the different technological approaches, each type of illumination has its respective strengths that can be used for different inspection tasks. For example, if the surface of the object is very reflective, then dome lighting can prevent reflections. If cameras and vision sensors are intended to recognize scratches or engravings, lateral dark field lighting is recommended.

除了确定应使被测物体的哪些部分可见外，还需要考虑其他方面的因素，例如材料特性（如表面性质和颜色）、环境条件（如外部入射光）或工作距离。

采用不同颜色的光源可以形成鲜明的对比，从而更好或更有效地完成检测任务。因此，有时候不必使用彩色相机。在黑白成像中，彩色光源还可以起到增强或抑制特定颜色的作用。例如，如果不同颜色的表面（如彩色铅笔）暴露在蓝光下，那么蓝色表面的反光性最强，而其他表面则会不同程度地吸收光线，具体取决于表面颜色。由此产生的图像效果是：蓝色铅笔显得非常亮，而以红色为主色调的区域则显得非常暗。通过这种方式可以形成明显的对比，这将决定应用解决方案是否能够成功。

找到满足应用要求的合适光源需要考虑许多因素。这一过程极具个性化，而且可能非常复杂。如果您有任何疑问，我们很乐意为您提供建议，帮助您找到理想的解决方案。