When using the endoscope for testing, the following factors should be considered as the basis for selecting the endoscope equipment: check the size of the extension hole. Examining the size of the extension hole will limit the diameter (or working diameter) of the endoscope tube. Approach path to the detection point. If the approach path to the detection point is linear, it is more suitable to use rigid endoscope for detection. If it is a curved (or tortuous) approach path, soft optical fiber endoscope or electronic image endoscope must be used.

Check the position of the insert hole. During the detection, the objective lens of the endoscope hole detector must be extended close enough to the detection point (or subject) to carry out the detection work. The inspection of the position of the extension hole will determine the observation direction, approach route and working length of the endoscope. If there is not enough room at the inspection entrance, the inspector may need an adjuster connected to the eyepiece to obtain the most appropriate viewing Angle.

Distance from objective to subject. Whether using standard or high-intensity light sources, the distance between the objective lens and the subject will directly affect the lighting demand, and the objective lens needs to use the best Angle of view to obtain the best image resolution and maximum magnification. Defect size. The size of the defects varies greatly, from hairline cracks to large damage cracks. The size of these defects is an important reference factor for selecting the magnification, Angle of view, focusing ability and lens resolution of the endoscope hole finder, so as to obtain appropriate and clear defect images. In general, large viewing angles can quickly scan a wide range of objects and avoid the loss of part of the subject images during detection.

The outline size of subject. The size of the subject's outline, including the entire subject, cracks or cracks, and deformations, is one of the most important factors in determining the Angle of view and the brightness of the light source. Endoscopic hole finder if client objects in a detection area through long or too deeply, some parts of the tested object may be on a different plane, so the adoption of endoscopic system must have enough focusing function, so that you can in a fixed position, to capture the different distance clearly or depth of object image, tested and fully to the tester. The Reflectivity of light. For those dark surfaces coated with carbon paint, due to their poor reflectivity of light, they need a stronger lighting effect to obtain a better image of the subject.