Application of TOD method in TV resolution test of CCD camera

This paper applies triangle orientation discrimination (TOD) method in TV resolution test of CCD camera. The TOD method uses equilateral triangle patterns of different orientations and sizes to replace the normal bar patterns; the observer's task is to identify the orientation of the triangles rather than to discriminate the bar patterns. Based on the Johnson criterion, this paper quantitatively relates the orientation discrimination of 2-D object with the resolvable numbers of bar patterns across the object critical size. A new test chart with triangle patterns was designed and used in TV resolution test of CCD camera. Experiments reveal that the non-periodical triangle patterns effectively avoid the beat effect of periodical bar patterns; the observer's task is unambiguous and easy to perform. Thus the proposed TOD method can greatly improve the accuracy and consistency of camera resolution test.