| 摘要 |
PURPOSE:To automatically set a proper contrast and density by calculating a weight coefficient and a bias component based on the feature values showing the variation degree and the average value of the differential image data. CONSTITUTION:Two picture data S1 and S2 are provided to show the two radiation pictures of the same subject together with the 1st and 2nd weight coefficients W1 and W2, and a bias component C. Then the subtraction picture data S3 is obtained by changing successively the weight coefficient ratio alpha= W1/W2. At the same time, the differential picture data SO is obtained based on a formula SO = alpha.S1 - S2. Then the 1st and 2nd feature values are obtained to show the variance degree and the average value of the data SO respectively. Furthermore the coefficient W2 and the component C are obtained based on the 1st and 2nd feature values respectively. As a result, a proper contrast and density are automatically set.
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