Method for operating a geodetic instrument, and related geodetic instrument

A method for operating a geodetic instrument comprising an optical source for assisting a user in aiming at a target in a scene by emitting optical pulses forming a spot at the target, and an imaging device, wherein the imaging device and the optical source share a common optical channel within the geodetic instrument, the method comprising:

• capturing a plurality of images with the optical source turned on;
• determining a lowest registered intensity level of each pixel of the imaging device among the plurality of images;
• obtaining a reference image using said determined lowest registered intensity level for each respective pixel of the imaging device, the reference image representing crosstalk occurring in the common optical channel;
• capturing a to-be processed image with the optical source turned on;
• and
• processing the captured to-be processed image with the reference image for removing crosstalk from the to-be processed image.