assurance by a diagnostic on the basis of relatively with regard to the large number of parameters in thermal spray coating small quantities of data and based on representative and unique data for the spray coating method or the spraying device with regard to the spraying device burner the following conclusions can be drawn directly from the geometrical surface regions or preferably their data records state of the electrodes enthalpy changes in the free jet and the enthalpy distribution in the free jet velocity of the discharged gas separation of the ultrasonic nodes enthalpy changes in the free jet and the enthalpy distribution in the free jet the following characteristics of the spray coating method i e the particular jet can for example be recorded from the geometrical surface regions or preferably their data records 1 melting behavior 2 aperture 3 center of mass and 4 direction the present invention will now be described in more detail with the aid of an example fig1 shows the individual stages of an image processing method for quality assurance in thermal spray coating in accordance with the present invention e g plasma coating as a series of images the individual stages are the sequence of images is based on a computer processing and or encoding method in accordance with the present invention areas of equal intensity in the exposed image sections are marked by a contour detection algorithm a gradient steps representation or a.