Selecting Control Points

The following figure shows these components of the Control Point Selection

Tool.

Detail windows

Input

Base

Overview windows Input

Base

Detail rectangles

Input

Base

Using Navigation Tools to Explore the Images

To find visual elements that are common to both images, you might want to change the section of the image displayed in the detail view or zoom in on a part of the image to view it in more detail. The following sections describe the different ways to change your view of the images:

•“Using Scroll Bars to View Other Parts of an Image” on page 7-18

•“Using the Detail Rectangle to Change the View” on page 7-18

•“Panning the Image Displayed in the Detail Window” on page 7-19

•“Zooming In and Out on an Image” on page 7-19

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7 Image Registration

•“Specifying the Magnification of the Images” on page 7-20

•“Locking the Relative Magnification of the Input and Base Images” on page 7-21

Using Scroll Bars to View Other Parts of an Image

To view parts of an image that are not visible in the Detail or Overview windows, use the scroll bars provided for each window.

As you scroll the image in the Detail window, note how the Detail rectangle moves over the image in the Overview window. The position of the Detail rectangle always shows the portion of the image in the Detail window.

Using the Detail Rectangle to Change the View

To get a closer view of any part of the image, move the Detail rectangle in the Overview window over that section of the image. cpselect displays that section of the image in the Detail window at a higher magnification than the Overview window.

To move the detail rectangle,

1Move the pointer into the Detail rectangle. The cursor changes to the fleur shape, .

2Press and hold the mouse button to drag the detail rectangle anywhere on the image.

Note As you move the Detail rectangle over the image in the Overview window, the view of the image displayed in the Detail window changes.

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Selecting Control Points

Panning the Image Displayed in the Detail Window

To change the section of the image displayed in the Detail window, use the pan tool to move the image in the window.

To use the pan tool,

1Click the Pan button in the Control Point Selection Tool toolbar or select Pan from the Tools menu.

2Move the pointer over the image in the Detail window. The cursor changes to the hand shape, .

3Press and hold the mouse button. The cursor changes to a closed fist shape,

. Use the mouse to move the image in the Detail window.

Note As you move the image in the Detail window, the Detail rectangle in the Overview window moves.

Zooming In and Out on an Image

To enlarge an image to get a closer look or shrink an image to see the whole image in context, you can zoom in or zoom out on the images displayed. (You can also zoom in or out on an image by changing the magnification. See “Specifying the Magnification of the Images” on page 7-20 for more information.)

To zoom in or zoom out on the base or input images,

1Click the appropriate magnifying glass button on the Control Point Selection Tool toolbar or select Zoom In or Zoom Out from the Tools menu.

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7 Image Registration

2Move the pointer over the image in the Detail window that you want to

zoom in or out on. The cursor changes to the appropriate magnifying glass shape, such as . Position the cursor over a location in the image and click the mouse. With each click, cpselect changes the magnification of the image by a preset amount. (See“Specifying the Magnification of the Images” on page 7-20 for a list of some of these magnifications.) cpselect centers the new view of the image on the spot where you clicked.

Another way to use the Zoom tool to zoom in on an image is to position the cursor over a location in the image and, while pressing and holding the mouse button, draw a rectangle defining the area you want to zoom in on. cpselect magnifies the image so that the chosen section fills the Detail window. cpselect resizes the detail rectangle in the Overview window as well.

The size of the Detail rectangle in the Overview window changes as you zoom in or out on the image in the Detail window.

To keep the relative magnifications of the base and input images synchronized as you zoom in or out, click the Lock ratio check box. See “Locking the Relative Magnification of the Input and Base Images” on page 7-21 for more information.

Specifying the Magnification of the Images

To enlarge an image to get a closer look or to shrink an image to see the whole image in context, use the magnification edit box. (You can also use the Zoom buttons to enlarge or shrink an image. See “Zooming In and Out on an Image” on page 7-19 for more information.)

To change the magnification of an image,

1Move the cursor into the magnification edit box of the window you want to change. The cursor changes to the text entry cursor.

2Type a new value in the magnification edit box and press Enter, or click the menu associated with the edit box and choose from a list of preset

magnifications. cpselect changes the magnification of the image and displays the new view in the appropriate window. To keep the relative magnifications of the base and input images synchronized as you change the magnification,

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