1. A computer implemented method for adaptive binarization to remove a defect from an image, the method comprising: receiving data representing at least one bit plane of an image; blurring the bit plane through an image processing operation; analyzing the blurred bit plane to identify a positional boundary for a defect in the image data; and processing the bit plane to remove the defect, wherein a first threshold value is used for data within the positional boundary and a second threshold value is used for data outside the positional boundary.