Cameras or 3D scanners - what to choose and when? - Scanway

Cameras or 3D scanners - what to choose and when?

A common dilemma when implementing machine vision is the decision to choose between: cameras and scanners? Here are our suggestions.
Mikołaj Podgórski

COO Scanway

Cameras in vision systems

The most common approach in the making of vision systems is the use of sets of one or more cameras with lighting, optics, and appropriate software. They work very smoothly and adapt to the moving production line while recording the image. The software performs an analysis and refers to the recorded pattern, verifying the shapes, dimensions, and colors of the tested object. The system verifies that there are no deficiencies or that the product has been properly assembled. In case of any inconsistencies, the software informs about detected deviations from the norm. Thanks to that in the final stage of production we receive the highest quality product.

Industrial cameras are perfect for high-speed production lines in a compacted space. They generate high-resolution images without a need to stop the line. We can choose from linear, 2D, and 3D cameras, which additionally provide information about the shape and geometry of the product. This set of information definitely develops the quality control process.

Scanners in vision systems

In the process of vision quality control, it is also possible to use 3D scanners. They are able to create three-dimensional models based on an existing object. The device maps the shape of the object by combining a set of points and creating digital clouds from them, which are then processed and combined into a complete mesh model. This allows even very complex geometry to be mapped quickly and accurately. However, in order to be able to get information about the whole object, several measurements have to be made.

3D scanners can use two technologies: laser or structured light. Laser technology is characterized by high precision and allows the analysis of objects in difficult lighting conditions, which, however, is associated with longer data processing time. Devices based on structured light projection are characterized by high speed and lower price but are more sensitive to lighting conditions than laser scanners.

kamery i skanery w systemach wizyjnych-min

One of the biggest advantages of 3D scanners is their high accuracy and resolution. The precision of measurement can reach up to the order of thousandths of a millimeter. As with cameras, the technology allows us to detect an object and compare it with a model. However, by comparing not the image but the 3D model, we can evaluate the geometry and check whether it is compatible with, for example, a reference CAD model. The data obtained in this way can be used to decide whether to accept or reject the product. When purchasing a scanner, it is necessary to consider the specific operating conditions on the production line. Variable temperature, humidity, and lighting, significantly affect the quality of the obtained results. This type of system works best where lighting can be controlled. When deciding to buy the equipment, one should also take into account its cost, in this case, higher than cameras. Depending on the parameters and type of the device, it ranges from several to several hundred thousand EUR.

Cameras vs scanners

Each of the described technologies has undoubted advantages and it is not a good practice to unanimously settle the superiority of one over the other. Both cameras and 3D scanners improve the quality of the control process with very high accuracy. However, the choice of an appropriate solution depends on individual expectations and conditions in which the system would work. The most important thing is to adapt the choice of appropriate equipment to the needs and requirements of your own implementation.

Do you have any Questions about camera or scanner selection? Contact us!

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