It is known that parameters such as the feed rate and the spindle speed affect the hole quality during the drilling of aluminium and its alloys. In particular, deflection occurs as a result of the increase or decrease of the reverse forces acting on the tool as a result of changing the parameter values. The tool deflection causes deviations in the hole geometry. This requires the initial detection of the deflection on the tool and then the most appropriate updating of the drilling parameters. At the present time, force-based estimation and inductive or laser sensor detection methods are used for the detection of tool deflection. These methods are useless because they require expensive measurement systems and continuous fine-tuning. This study aimed to calculate the tool deflection that occurs during the drilling of AL 7075 material using an image processing technique. In the experiments using different drilling parameters, the tool deflection was calculated and the effects of the parameters on tool deflection were investigated. As a result, it is shown that the tool deflection can be detected quickly and simply by image processing. In addition, the effects of the processing parameters on the tool deflection are discussed.