Optimal inspection method for imaging the inner surface of a cylindrical object using a CCTV lens

1. How to observe the inner wall surface of a cylindrical object with a CCTV lens

When observing the inner wall surface of a cylindrical object using a CCTV lens, there is a method of capturing divided images using multiple cameras from an angle. In that case, since the work surface of the cylindrical object is curved with respect to the lens, the entire screen will not be in focus. "Proposal of a lens that solves the out-of-focus problem that occurs during oblique imaging in visual inspection of substrates and foreign matterEven if you use the Scheimpflug mechanism introduced in ", the focus problem cannot be solved, so there are many cases where the brightness of the lighting is increased, the aperture of the lens is narrowed down, and the depth of field is used to "escape" and shoot. .

2. Inspection method using a cylindrical mirror

This out-of-focus phenomenon occurs because the workpiece is curved, and can be improved by photographing through a reverse-curved cylindrical mirror, which is offset.

Opto Engineering's PCHI series also has drawbacks such as "restrictions on workpiece input accuracy and WD cannot be earned depending on the size of the workpiece". On the other hand, oblique photography with CCTV and telecentric lenses is less likely to suffer from these difficulties, and there is also the advantage that the resolution of inspection and measurement can be increased because the work is divided and photographed.

If you are not satisfied with the results of the PCHI series, we also accept orders for customized CCTV lenses and curved mirrors to meet your needs.