Influence of test chart contrast on quantification of photo sharpness

Abstract

Quality control of digital photos is evolving rapidly every day. Procedures and methods of measurement are changing. Cameras on mobile phones are currently in focus because they are largely replacing the cameras used so far. Based on the standards for the control of photos on mobile phones, in this paper one of the essential quality attributes was chosen to be tested, which is the sharpness of the photos. For the purposes of the experiment, five commercially available mobile phones with different rear camera characteristics were selected. Two standard test cards with different contrast ratios were used. The tests were carried out under appropriate laboratory conditions. Sharpness is analaziry via MTF50 value as measured in Imatest software. Based on the results, it is concluded that the contrast of the test chart affects the measured value, therefore it is important to strictly define the conditions of measurement and the used test card when analyzing this attribute.