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How can I use a area scan camera for defect detection on metal sheet surface being rolled from speed 2 m/sec to 15 m/sec depending upon product? My field of view is 1900 mm. How will i synchronize speed of sheet with camera for accurate distance mapping of defect?
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Hi Hrithik, I'd recommend using a line scan camera(s) to do this work along with a linear light. The line scan camera should be triggered by a speed encoder attached to the roller or conveyor. This will keep the camera synchronized and allow you to determine where the defects are located. However, you may decide to use some type of marking system as well when the defects are found. The resolution of the camera and the type of light depends upon the type and size of defect you wish to detect. If the defect is a scratch or a raised defect like a crease or particle then a dark field type of light is preferred in which the light is glancing the surface of the sheet of steel. There is a lot of on line descriptions to this technique. Teledyne Dalsa has good technical articles on how to use line scan cameras for your application. If the defects are small, then you may have to use more than one camera side by side to cover the width of the steel. I hope this is of help to you
For the synchronisation you can use an encoder. For your field of view you might have to use more than one camera.
Hi , I would recommand a line scan camera and a encoder at the transport axis, so you get a nearly endless image, after all it's much easier to design a light for a line scan camera. Hope this will help you, feel free to contact me for further details. Best regards Michael