A method for producing a biometric image using an optical biometric imaging arrangement configured to be arranged under an at least partially transparent display panel and configured to capture an image of an object located on an opposite side of the at least partially transparent display panel, the optical biometric imaging arrangement including a set of microlenses adapted to redirect incoming light onto a photodetector pixel array , the method comprising: capturing (S104) a biometric image of the object including a set of sub-images using the optical biometric imaging arrangement; retrieving (S602) an illuminance calibration image including a set of sub-images; and normalizing (S110) the biometric sub-images for providing a normalized biometric image based on the normalized biometric sub-images; characterised in that the method further comprises computing (S604) a mathematical model of the imaging roll-off effect in the illuminance calibration sub-images caused by the microlenses, applying (S608) the mathematical model to the sub-images of the illuminance calibration image to at least partly remove the roll-off effect from the illuminance calibration sub-images to produce masking calibration sub-images; storing (S612) the masking calibration sub-images that have been subject to the mathematical model in a memory; estimating (S106) a spatial transformation, being at least a horizontal displacement in the plane of the display panel and/or an image sensor of the optical biometric imaging arrangement, between the at least one biometric sub-image and corresponding masking calibration sub-images, the masking calibration sub-images indicative of a masking effect caused by the display panel; and applying (S108) the spatial transformation to retrieved illuminance calibration sub-images adapted for illuminance calibration for captured biometric sub-images to align the illuminance calibration sub-images with the biometric sub-images; wherein the biometric sub-images are normalized using the aligned illuminance calibration sub-images. capturing (S104) a biometric image of the object including a set of sub-images using the optical biometric imaging arrangement; retrieving (S602) an illuminance calibration image including a set of sub-images; and normalizing (S110) the biometric sub-images for providing a normalized biometric image based on the normalized biometric sub-images; characterised in that the method further comprises computing (S604) a mathematical model of the imaging roll-off effect in the illuminance calibration sub-images caused by the microlenses, applying (S608) the mathematical model to the sub-images of the illuminance calibration image to at least partly remove the roll-off effect from the illuminance calibration sub-images to produce masking calibration sub-images; storing (S612) the masking calibration sub-images that have been subject to the mathematical model in a memory; estimating (S106) a spatial transformation, being at least a horizontal displacement in the plane of the display panel and/or an image sensor of the optical biometric imaging arrangement, between the at least one biometric sub-image and corresponding masking calibration sub-images, the masking calibration sub-images indicative of a masking effect caused by the display panel; and applying (S108) the spatial transformation to retrieved illuminance calibration sub-images adapted for illuminance calibration for captured biometric sub-images to align the illuminance calibration sub-images with the biometric sub-images; wherein the biometric sub-images are normalized using the aligned illuminance calibration sub-images. <EOS>