An apparatus for quality testing a body having a surface comprising a structuring bounded by edges and a substantially edge-free unevenness, wherein the structuring does not constitute a quality impairment, and wherein the unevenness constitutes a potential quality impairment, comprising: a means for generating a height representation of the surface, wherein the means for generating the height representation of the surface is configured to generate the height representation of the surface, so that the height representation of the surface includes the structuring and the unevenness; a means for calculating a variation representation from the height representation, wherein the means for calculating the variation representation from the height representation is configured to calculate the variation representation from the height representation by differentiating the height representation, so that the first derivative of the height representation which the variation representation represents is obtained, and so that the variation representation includes variations of the height representation, so that at a boundary of the structuring a high variation is obtained, whereas at a boundary of the unevenness a low variation is obtained; and a means for detecting regions of the height representation, wherein the means for detecting the regions of the height representation is configured to use a predetermined variation threshold value which is lower than the high variation and greater than the low variation, and wherein the means for detecting the regions of the height representation is further configured to detect, by means of a threshold value decision using the predetermined variation threshold value, only such regions of the height representation comprising a variation whose magnitude is smaller than the predetermined variation threshold value as potentially quality-affecting regions. a means for generating a height representation of the surface, wherein the means for generating the height representation of the surface is configured to generate the height representation of the surface, so that the height representation of the surface includes the structuring and the unevenness; a means for calculating a variation representation from the height representation, wherein the means for calculating the variation representation from the height representation is configured to calculate the variation representation from the height representation by differentiating the height representation, so that the first derivative of the height representation which the variation representation represents is obtained, and so that the variation representation includes variations of the height representation, so that at a boundary of the structuring a high variation is obtained, whereas at a boundary of the unevenness a low variation is obtained; and a means for detecting regions of the height representation, wherein the means for detecting the regions of the height representation is configured to use a predetermined variation threshold value which is lower than the high variation and greater than the low variation, and wherein the means for detecting the regions of the height representation is further configured to detect, by means of a threshold value decision using the predetermined variation threshold value, only such regions of the height representation comprising a variation whose magnitude is smaller than the predetermined variation threshold value as potentially quality-affecting regions.