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<strong>Imatest</strong> <strong>Documentation</strong><br />

you'll have a chance to refine it.<br />

For Slanted-Edge SFR, select the region you want. Recommended cropping.<br />

For Log Frequency (simple), select a narrow strip running from along the direction of increasing spatial frequency. Narrow strips<br />

of the Log Frequency-Contrast chart can be used.<br />

For Log F-Contrast, select most of the chart image, leaving small margins (1/2 to 1% of the image dimensions) at the edges.<br />

After the rough crop has been selected, the fine adjustment box appears, showing the coarse crop as a rectangle. This dialog box<br />

can be enlarged or maximized to facilitate the adjustment. It offers numerous options.<br />

Crop for the Log Frequency-contrast chart. Leave a small margin<br />

(1/2 - 1% of the image height) at the top and bottom.<br />

The entire ROI can be moved ( ^ > v < , upper-left).<br />

The top, bottom, left, or right sides can be moved ( T^ Tv R> R< B^ Bv L> L< , middle-left).<br />

You can choose between Fine, Coarse, and Extra Coarse movement (1, 5, or 25 pixels of movement per click).<br />

The display can be zoomed out or in.<br />

Pixel values for the four corners can be entered (X(tl), Y(br), ..., where tl = top-left, br = bottom right, etc.). The origin is the<br />

upper-left. Be sure to press the Enter key after entering a value.<br />

When you have completed the fine adjustment, click one of the buttons on the bottom of the window. If you click Yes,<br />

Continue , an additional dialog box may appear. The entries in this dialog box can be changed later by clicking on Image<br />

settings & options in the Rescharts window. If you click Yes, Continue in Express mode , it will go directly to the<br />

Rescharts window, using saved (recent) values.<br />

The Rescharts window<br />

After the image file has been entered, calculations are performed and the most recent Chart view is displayed. The MTF/contrast (2D<br />

pseudocolor contour) display (actual MTF when a sine chart is used) for Log F-Contrast is shown below.<br />

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