4 Displaying and Exploring Images

Modifying Image Data

By default, the Adjust Contrast tool adjusts the values of the pixels used to display the image in the Image Tool but does not change the actual image data. To modify pixel values in the image to reflect the contrast adjustments you made, you must click the Adjust Data button.

The following example illustrates this process.

1Display an image in the Image Tool. The example opens an image from a file. imtool('moon.tif');

2Start the Adjust Contrast tool by clicking the Adjust contrast button, , or by selecting Adjust Contrast from the Tools menu in the Image Tool.

3Adjust the contrast of the image. Use one of the mechanisms provided by Adjust Contrast tool, such as resizing the window over the histogram. See “Using the Histogram Window to Adjust Image Contrast” on page 4-46. You can also adjust contrast using the Window/Level tool, moving the pointer over the image.

4Adjust the image data to reflect the contrast adjustment you just made. Click the Adjust Data button in the Adjust Contrast Tool. When you click the Adjust Data button, the histogram will update. You can then adjust the contrast again, if necessary. If you have other interactive modular tool windows open, they will update automatically to reflect the contrast adjustment.

Note The Adjust Data button is unavailable until you make a change to the contrast of the image.

Saving the Modified Image Data

By default, if you close the Image Tool, it does not save the modified image data. To save these changed values, use the Save As option from the Image Tool File menu to store the modified data in a file or use the Export to Workspace option to save the modified data in a workspace variable.

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