4 Displaying and Exploring Images

Note You can also use the Window/Level tool to adjust contrast and brightness using the mouse. (The name comes from medical applications.) Click Window/Level in the Image Tool toolbar or select the Window/Level option from the Image Tool Tools menu. For more information about using the Window/Level tool, see “Using the Window/Level Tool to Adjust Image Contrast” on page 4-47.

When you close the Adjust Contrast tool, the Window/Level tool remains

active. To turn off the Window/Level tool, click the Window/Level button or one of the navigation buttons in the Image Tool toolbar.

Using the Histogram Window to Adjust Image Contrast

To adjust image contrast using the Adjust Contrast tool, you manipulate the size of the red-tinted window displayed over the histogram, using any of the following methods.

•Grabbing one of the red handles on the right and left edges of the window and dragging it. You can also change the position of the window by grabbing the center line and dragging the window to the right or left.

•Specifying the size and position of the window in the Minimum and Maximum fields. You can also define these values by clicking the dropper button associated with these fields. When you do this, the pointer becomes an eye dropper shape. Position the eye dropper pointer over the pixel in the image that you want to be the minimum (or maximum) value and click the mouse button.

•Specifying the size and position of the window in the Width and Center fields.

•Selecting the Match data range button in the Scale Display Range part of the tool. When you choose this option, the size of the window changes from the default display range to the data range of the image.

•Trimming outliers at the top and bottom of the image data range. If you select the Eliminate outliers option, the Adjust Contrast tool removes the top 1% and the bottom 1%, but you can specify other percentages.

When you specify a percentage, the Adjust Contrast tool applies half the

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