The Meaning Behind Each Letter in the VSOP Method
Each letter in “VSOP” stands for:
Vector (direction),
Silhouette,
Optical (optical-based),
Pattern recognition.
This method is an evolution of what we call the “Kome-no-Ji” method (“米の字法”). If a defect can be clearly seen in a single still image, then the Kome-no-Ji method is the most effective approach for inspection.
However, one of the most challenging types of defects—especially common in visual inspection of automotive components—is a defect that disappears depending on the viewing angle or position.
For instance, with metal parts, even skilled inspectors often tilt the part toward the light and say, “Ah, there it is,” when they finally notice the flaw. In camera-based image inspection, it’s not uncommon to wonder, “Why did this defect pass inspection?”—only to realize the flaw wasn’t visible to the camera at the time. This can lead to costly outcomes, like needing to re-inspect every item in the lot.
To address this issue, we developed the VSOP method, which involves:
Projecting a moving grid pattern onto the object using a projector, eliminating defects that “disappear” based on angle or position.
Comparing all visible surface features—such as fine bumps, scratches, and dents—using vector (directional) analysis against reference (non-defective) data.
As long as the defect is visible in some way, this method will detect it as a distortion in form. That is the core of the VSOP approach.
←Projecting a moving grid pattern with a projector
↑Cylinder head with projected grid pattern
The VSOP Method: A New Path in Visual Inspection
The VSOP method can be considered a type of structured light scanning. It enables reliable 3D inspection by visualizing even minute surface irregularities—bumps or dents that might be invisible in still images, or disappear depending on the object’s position.
Additionally, the continuous black-and-white stripe pattern acts like a moving triangular wave, serving as a subtle but powerful visualization tool. This dynamic pattern reveals faint scratches or stains that are otherwise difficult to detect in 3D data alone, making it remarkably effective for capturing such delicate flaws.
In this way, the VSOP method combines both 2D and 3D inspection capabilities, offering a groundbreaking approach in the field of visual inspection.
Since verbal explanation can only go so far, we’ve prepared a short video summarizing the full process—from reference model learning to defect detection. Please take a look.
Current Status and Invitation
We have already received several inquiries and are actively refining the system for real-world inspection operations.
In particular, we’ve received strong feedback from the automotive industry, especially in applications involving cast parts, machined surfaces, sheet metal, and plastic molded components.
Many have told us that “this is on a completely different level from anything we’ve seen before.”
And that is no exaggeration.
With the VSOP method, we can now offer a completely new solution for defects such as dents, scratches, and surface irregularities—issues that were often missed because they disappeared depending on the viewing angle.
We invite you to send us a sample part.
We would be happy to demonstrate how our system performs on your actual workpieces.
In addition to the video above showing the full flow from reference model learning to inspection,
we also have Part 2 and Part 3 available.
You can find them under the “Inspection Examples on Various Workpieces” widget on the right side.
We encourage you to take a look.
