A device for testing a flat plate-shaped material

A method for examining and detecting foreign objects in a flat plate-shaped material, the method comprising:

• providing a device comprising a transport device adapted for transporting a flat plate-shaped material to be examined through the device in a transport direction, a first X-ray source adapted for, in operation, emitting a first X-ray beam, and a second X-ray source adapted for, in operation, emitting a second X-ray beam, the first X-ray source and the second X-ray source being arranged on a first side of the transport device, a first sensor unit arranged to detect the first X-ray beam and a second sensor unit arranged to detect the second X-ray beam, the first sensor unit and the second sensor unit being arranged on a second side of the transport device opposite to the first side of the transport device seen in a vertical direction, wherein the first X-ray source and the second X-ray source are arranged spaced apart in the transport direction and are arranged such that the direction of propagation of the first X-ray beam and the direction of propagation of the second X-ray beam are tilted towards each other forming an angle of at least 5 degrees with one another,
• using the first sensor unit, detecting first data indicative of the presence of a foreign object in a flat plate-shaped material and of an indirect or a direct position in the transport direction of a foreign object in the flat plate-shaped material,
• using the second sensor unit, detecting second data indicative of the presence of a foreign object in a flat plate-shaped material and of an indirect or a direct position in the transport direction of a foreign object in the flat plate-shaped material, and
• by the data processing unit:
• receiving detected first data and second data from the first sensor unit and the second sensor unit,
• processing the received first data and second data to determine the presence of a foreign object in the flat plate-shaped material by evaluating the intensity of the X-rays detected by the first sensor unit and the second sensor unit as a function of horizontal position in the flat plate-shaped material such as to detect an intensity that differs significantly from the intensity of X-rays transmitted through the remaining flat plate-shaped material, and
• if the presence of a foreign object in the flat plate-shaped material is determined positively, processing the received first data and second data to provide at least a measure of the vertical position of the foreign object in the flat plate-shaped material and a measure of a horizontal position of the foreign object in the flat plate-shaped material.