论光源对影像测量仪的重要性 On the Importance of Light Sources for Image Measuring Instruments

光源在影像测量仪中是必不可少的一部分。从测量的角度出发，影像测量仪有表面光、轮廓光及同轴光，好的光源，能够让测量的数据更加的稳定，更准确。

Light sources are an indispensable part of image measuring instruments. From the perspective of measurement, image measuring instruments have surface light, contour light, and coaxial light. A good light source can make the measurement data more stable and more accurate.

轮廓光是一种逆光照明，所以通常这个光是装在影像测量仪工作台的背面，它主要照射的是零件的背部，在成像时，我们是得不到物体表面的特征，但是能够清晰的得到零件的外观轮廓。轮廓光可以使透明和不透明区分开来，透明的地方会呈现出白色，不透明的地方呈现出来黑色（如下图），明暗对比，在测量识取特征时，精确实际测量。

Contour light is a kind of backlighting, so it is usually installed on the back of the image measuring instrument's worktable. It mainly illuminates the back of the part. During imaging, we cannot obtain the surface features of the object, but we can clearly obtain the external contour of the part. Contour light can distinguish transparent from opaque areas. Transparent areas appear white, while opaque areas appear black (as shown in the figure below). This contrast between light and dark allows for precise actual measurement when identifying and extracting features.

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表面光一般采用的是环形光源，一般与影像测量仪的镜头和相机是在同一个方向上的，它主要是测量表面的特征尺寸，由于有的零件表面是比较复杂的，环形光同时照射时是不能够清楚的看到成像，所以我们现在可以采用分区照明，来达到我们想要的影像成像效果。

Surface light generally uses a ring light source, which is usually in the same direction as the lens and camera of the image measuring instrument. It is mainly used to measure the characteristic dimensions of the surface. Since the surface of some parts is relatively complex, clear imaging cannot be achieved when the ring light illuminates simultaneously. Therefore, we can now adopt zoned illumination to achieve the desired image imaging effect.

同轴光是一种与相机同轴方向的光源，他主要作用于零件的深孔及盲孔深度，而且对测量透明反光的零件有独特的用处，对抓取零件元素的准确性有很强的辅助作用。

Coaxial light is a light source that is coaxial with the camera. It mainly acts on the depth of deep holes and blind holes in parts, and has unique uses for measuring transparent and reflective parts. It also provides strong assistance in accurately capturing part elements.

数据测量的准不准确，就要看光照的好不好。所以，光源在影像测量仪中是非常至关重要的一个点，另外光源的作用还有照亮目标，提高亮度；形成有利于图像处理的效果；克服环境光干扰，保证图像的稳定性；用作测量的工具或参照物。

Whether the data measurement is accurate or not depends on whether the illumination is good. Therefore, the light source is a crucial point in image measuring instruments. In addition, the functions of the light source also include illuminating the target and improving brightness; forming effects that are conducive to image processing; overcoming ambient light interference to ensure image stability; and serving as a measurement tool or reference.