Linghou Robotics' independently developed oblique telecentric lens product, through a special design, can be used for tilt measurement when the plane of the object being measured is not perpendicular to the optical axis of the lens. It can achieve clear imaging within the designed tilt angle range, while still retaining the low telecentricity and low distortion characteristics of ordinary telecentric lenses.
1. Main features
o Using the Scheimpflug regulation mechanism
o Image without radial distortion
o Excellent telecentricity
2. Application Scenarios
o Can be used for tilt measurement where the plane of the object being measured is not perpendicular to the optical axis of the lens.
o Defect detection
o Character recognition
3. Application Solutions
o Defect detection
o Character recognition
o Visual system simplification
4. Case Introduction
The object under test is a charging head, as shown in the image above. It is necessary to detect and identify the characters on its inner wall. Because the characters are on the inner wall of the object, the lens needs to be tilted for shooting.
The comparison test results are as follows
1) Ordinary telecentric lens (the camera and lens are tilted together at 60° relative to the inner wall of the object)
o Camera: 2/3”
o Lens: TCA V23-05-110
o Light source: LT-24V-72R30-W
2) Telecentric lens with oblique image (the camera is tilted 45° relative to the inner wall of the object, and the lens is tilted 15° relative to the camera, at which point the lens is tilted 60° relative to the inner wall of the object)
o Camera: 2/3"
o Lens: TCSSMV23-05-110
o Light source: LT-24V-72R30-W
The test results are as follows
The left image is taken with a standard telecentric lens; the right image is taken with an oblique telecentric lens.
The test results show that when a regular telecentric lens is tilted, only a portion of the image area can be clearly imaged, while when a tilted telecentric lens is tilted, the entire image area can be clearly imaged.
5. Other practical test cases
01. Check for presence or absence of coating on the side of terminal pins.
▼Imaging effect diagram
02. Inspection of raised areas and damage on the surface of black stickers
▼Imaging effect diagram
Images taken with a telecentric lens
In images taken with a standard telecentric lens, the light sources from left to right are, in order: a square shadowless light source, a ring light source, and a strip light source (oblique illumination).
03. Detection of surface characters and defects, side defects and glue on array-type electronic components.
▼Original product image
▼Imaging effect diagram
