Problems of Image Evaluation in Orthopedics Using Moiré Figures

Abstract

The generation of equal-height contour lines is a promising method for the complete, accurate, and form-fitting description of objects with irregular, threedimensional shapes. This problem exists in the field of medicine, because traditional measurements of human body forms with tape and calipers are no more sufficient. The increasing importance of such methods is indicated by the many attempts reported in the past [1]. But in most cases the point coordinates of the body surface had to be extracted before plotting the contour lines. This procedure was time-consuming or needed a complex equipment. None of them was accepted in clinical practice. A great interest arose in all methods, which are capable of generating contour lines as a first “integral” result - without the need of any analytical handling. One of them, the “Moiré-Topography” of TAKASAKI, was the starting point of a great number of studies for the determination of body volume, surface area and shape. Moiré - contouring is used for the evaluation of the face, of teeth and feet as well as for whole body photography in radiology and orthopedics [2, 3, 4, 5, 6]. Especially in orthopedics there is an increasing demand for description, documentation and evaluation of definite statements of structural abnormities and obvious asymmetries of the human body in the treatment of scoliosis [7, 8, 9, 10].