device for measuring velocity is integrated in an element of the forming table of the paper making machine 400 for instance the device could be integrated in the suction slot in one embodiment the capturing device s and or light source s are located in the headbox in another embodiment the light source s are integrated in the drainage strip below the paper web whereby the drainage strip is made out of a transparent and advantageously easily cleaned material such as plexiglass advantageously the device or devices are placed in a position somewhere between the headbox and the drying section of the paper making machine 400 fig5 is a flow chart illustrating a method for measuring the velocity of a moving web according to an aspect of the invention the method starts with step 501 which involves transmitting light from at least one light source through the paper web in step 502 the transmitted light is captured using at least one image capturing device in step 503 a first two dimensional image of a section of the paper web is produced based on the captured transmitted light from step 502 a second two dimensional image is then produced in steps 504 506 in step 504 light is again transmitted from at least one light source through the paper web as in step 501 in step 505 the transmitted light is captured using at least.