What Is a White Light Scanner?
A white light scanner is a camera and scanner combination that creates a three-dimensional (3D) scan of an object, primarily by using white light. This scan can be used for many things, such as for computer-aided design (CAD) drawings and reverse engineering. The white light scanner has to take many pictures to correctly assemble a 3D model, and the scanner may be manual or automatic. A fringe pattern, or a black-and-white line pattern, is used to ensure accuracy, to add contrast and to measure the object during the scan. Before pictures can be taken, dots and points are manually added to the object so the computer can correctly compile the object in 3D space.
Two cameras that project white light combine to make a white light scanner, which scans a physical object and models it in 3D space on the computer. Aside from making realistic scans of the depth, curve and size of an object, white light scanning also provides other uses. Information gathered from a scan can be added to a CAD program, allowing designers to make theoretical changes to an object. Parts also can be reverse engineered, so users can understand what makes objects or parts work.
To correctly make a 3D model, the white light scanner must take many images at different angles of an object. This ensures that the scanner accurately understands the object, so it can be properly assembled in the computer. Some scanners are automatic and take shots by themselves, but most are manual and users have to move the scanner around.
When taking an image, a white light scanner projects a fringe pattern on the object’s surface. One camera is responsible for projecting this pattern, while the other checks ambience and calibration. Using a fringe pattern makes it easier for the scanner to understand the size of the physical object and ensures accurate imaging. By using the fringe pattern, the object has optimal contrast, which helps the scanner pick up images.
Before using a white light scanner, users have to prep the object to be scanned. This involves adding little dots and larger point stickers to the object. One reason for this is that it further ensures imaging accuracy. Another reason is that, when the scanner takes a picture, it is really picking up these dots and points. The location information from the dots and points is compiled, which creates a realistic 3D representation.
@miriam98 - I don’t think the principle of adding dots to the object would work with really small machine parts, however.
For these object, there is probably another technique that is used; although I bet it’s similar. It would involve scanning of some sort to create the three dimensional outline.
@nony - That’s a good point. You could extend it by asking how many pictures you would need to take to form an accurate scan. The two go hand in hand in my opinion.
You’d need pictures taken from a lot of different angles to ensure the best possible model in the end. I suppose that from an engineering perspective, there are ways to determine exactly how many pictures to take, and from what perspective, depending on the size of the model.
I wonder how many dots and stickers have to be added to the object to create an accurate scan. If there are too few dots, you will have an oblique object that doesn’t map accurately to the depth of the original object.
I don’t think you could go wrong with having too many dots on the other hand; it will just create a more accurate three dimensional model.
I would imagine, as well, that you couldn’t place these dots just anywhere; there would have to be precise locations that would be ideal for properly representing the breadth and depth of the actual image.
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