KEYENCE VJ SERIES

We have purchased the multispectral illumination type of KEYENCE's GigE camera and lighting "VJ series" for evaluation and integration into our visual inspection system.
Currently, the integration work is in its climax.

This is "to integrate and control the camera and lighting so that images more suitable for inspection can be obtained," and overturns the conventional "common sense" of using a combination of camera and lighting from the camera manufacturer and lighting from the lighting manufacturer, respectively.

Split lighting is also offered by several lighting manufacturers. Although the process is the same in that one image is taken, the lighting is switched, and the next image is taken, "one image taken" = "one exposure + transmission," so if a 30 fps camera is used to switch 8 directions, it must "stand still" for about 8/30 seconds = 270 ms. On the other hand, in this system, the camera has a buffer and takes 8 exposures while switching lighting before transferring the images. Since the exposure time is on the order of 1 ms, the camera only needs to be stationary for 8 ms (since there is also a function to correct the position, there is no need to be completely stationary). As a result, in this system it is not visually obvious that the illumination is switching.
In the actual system, the system is stationary only during the exposure for higher speed, and transfers & inspections are performed during the object transfer. Since nothing can be done during the standstill time, there will be a marked difference in the throughput of the system.

To begin with, why is it necessary to switch the lighting? There are two major types of defects: defects that change the direction of reflected light due to a change in surface shape, and defects that change the color of the surface (change in scattering wavelength).
The latter is inspected for wavelength change = color change with less direct reflected light from the light source. The image is to see the change in light intensity for each color = each wavelength.
On the other hand, the former inspects that the amount of reflected light increases only when the inclination of the surface and the direction of the light source are in "good condition," making the surface appear "white. Since the direction of the surface tilt is not known, it becomes necessary to inspect the object "while changing the tilt of the object" by hand. The same effect can be achieved by changing the direction of the light source instead of changing the tilt of the object.
In other words, in order to deal with all kinds of defects, it is necessary to observe changes in light intensity while changing the wavelength and the direction of the light source.

The KEYENCE VJ series is the embodiment of this concept.
The multispectral illumination type can be switched between two modes: 8-wavelength illumination or 4-direction illumination.
・The LumiTrax illumination type can be switched between 8-direction illumination.

Our company decided, "For the time being, shape defects should be visible even in four directions. An environment that allows imaging from infrared to ultraviolet is attractive." We purchased a multispectral illumination type and prepared an environment that allows us to conduct experiments at any time. At the present time, we have found that it is possible to obtain epoch-making effects on scratches on metal surfaces (dirt and scratches are indistinguishable) after a long period of time.

The problem is that the initial cost will be high. However, considering that in the past it was necessary to prepare multiple inspection stages, many cameras, and many illuminators, the initial cost of the system as a whole can be expected to be reduced. In addition, as mentioned above, it can be expected to increase the processing speed of the equipment, which will also increase the operational effectiveness of the system.

This system is basically permanently installed in the company and can be touched at your leisure.