A SIMPLE METHOD FOR MEASURING MTF IN DIRECT DIGITAL INTRAORAL RADIOGRAPHY - TECHNICAL NOTE

Conventional methods for measuring the modulation transfer function re quire the exposure of a narrow slit or straight edge followed by compu tationally intense data analysis. An alternative method applicable to digital systems uses the standard deviation of gray levels within diff erent frequency regions of a bar pattern. To verify that this method g ave reliable results, measurements performed for two systems for intra oral radiography with the use of this method have been compared with m odulation transfer function values calculated from Fourier transformat ions of line spread functions measured for the two systems. The almost identical results confirm the consistency of both sets of modulation transfer function measurements and demonstrate the utility of the bar pattern method for performing rapid measurements.