1. An apparatus for correcting of at least one defect pixel value of an image sensor unit, the image sensor unit comprising at least a first and a second pixel array, wherein the image sensor unit is arranged to project representations of substantially the same image onto each pixel array, the apparatus comprising at least a first and a second input channel for receiving pixel values of the first and the second pixel array, respectively, wherein the apparatus is operable to replace a defect pixel value of the first pixel array with a corrected pixel value, wherein the corrected pixel value is determined from the values of neighbouring pixels of the defect pixel of the first pixel array, wherein the corrected pixel value is determined from values of a corresponding pixel and its neighbouring pixels of the second pixel array at the same pixel location as the defect pixel of the first pixel array with respect to the projected image, wherein the value of the corresponding pixel and/or the values of its neighbouring pixels are used to derive a confidence value for evaluating the values of the neighbouring pixels of the defect pixel in a weighted manner.