| 摘要 |
PURPOSE: To correctly evaluate the linearity of an edge even when the density of a form are uneven by correcting a variation quantity originating from the form for a measured value of density information on an image edge part according to the variation quantity of the density of the form. CONSTITUTION: A mean value calculating means 40 calculates the reflection factor mean value Rpave of a form part from the reflection factor distribution Ypi of the form part. A regression line calculating means 41 gives the gradient of a regression line as shown by a specific expression. Then, a standard deviation calculating means 42 calculates the standard deviation of a difference from the regression line of a reflection factor Yi at each sampling point. An edge error correcting means 434 calculates correction for removing variation of the form from the standard deviationσs by correction arithmetic from the standard deviationσp of the form part and the rate (a) of the exposure quantity of the form part included in the measured edge part of the image. Consequently, the value of the standard deviationσafter the variation in the reflection factor of the form is removed can be used to calculate an index obtained by digitizing only the disorder of the linearity of the edge of the evaluated image.
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