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iTool User's Guide: Working with Images |
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The iImage tool allows you many options to manipulate your existing image displays. Once you have visualized your image, you may rotate, flip, translate, scale, and zoom as well as modify image properties, scroll, and select image ROIs. The following options are available for manipulating images.
For more information on manipulation tasks which are common to iImage as well as other iTools, see Manipulating the Display.
The rotate operation makes it possible to rotate the image within the visualization by a specified number of degrees. To rotate your selected image, select Operations Transform
Rotate Data. For more information about rotating, see Rotation.
It is possible to scale the pixel values within an image by a specified scale factor. To scale your image, select Operations Transform
Scale Data. For more information on scaling data, see Scaling.
Note When working with byte data, the default byte scale range is always 0-255. Therefore, even if data ranges from 0-100, it will display using 0-255. This may cause visualized data to appear darker. |
You can also invert the data associated with your image, or with each channel of an RGB or RGBA image. If the data is byte data, the inversion occurs relative to the maximum byte value (255). Otherwise, the inversion occurs relative to the maximum data value per channel. To invert your image, select Operations Transform
Invert Image.
You can flip your image within the data space either horizontally or vertically. These operations flip the actual data associated with the image. To flip your data, select Operations Flip
Flip Horizontal or Operations
Flip
Flip Vertical.
View Zoom allows you to zoom in or out on a specific area of the image display area. To zoom in or out in View Zoom mode click Zoom on the toolbar or select a percentage value from the View Zoom droplist. For more information on working with View Zoom, see Zooming.
Canvas Zoom allows you to increase or decrease the magnification of the entire display canvas (which may contain multiple views, depending on the layout) by a specified percentage. Canvas Zoom is available by selecting a percentage from the Window Canvas Zoom menu. For more information on working with Canvas Zoom, see Zooming.
The pixel scale represents the number of window pixels used to display a single image pixel (horizontally and vertically). Pixel scaling is shown on the image panel (which appears on the right side of the iImage tool) and can be manipulated via the View Zoom manipulator on the iImage window toolbar and using its accompanying pull-down menu.
When an image is first loaded into iImage, the X and Y pixel scales are by default set to 100% (one window pixel is used to display one image pixel horizontally). Typically, when iImage first displays an image, the view zoom factor matches the X pixel scale. Changing the view zoom factor also updates the pixel scale labels.
If the currently selected image has been rotated, or if the visualization has switched to 3D (for example, because a surface was inserted), then the pixel scale labels are set to an empty string.
The iImage region growing operation lets you apply a region growing algorithm to the currently selected ROI. A new ROI is then created and displayed. To apply region growing to your ROI, select Operations Region Grow. You can then select the region grow method (by threshold or by standard deviation).
Annotations can be added to label or describe image visualizations displayed in the iImage tool.
The following types of annotations can be added to iImage displays:
For more information on creating and using annotations, see Adding Annotations.
You can plot image pixel values along a selected line. These values are extracted as a line profile of part of your image visualization and displayed in a new iPlot window:
Once a line profile has been drawn, it will remain until deleted. The line may be translated (or its endpoints moved individually). If it is translated or edited, the profile plot will automatically update.
If you dismiss your Plot Profile window and wish to have it back again, from your iImage window, with the line selected, choose Operations Plot Profile and the Plot Profile window will reappear.
Note Line profiles on map projections always connect points using the image coordinates (either degrees or meters). See Registering an Image for more information on image coordinates. |
To pan an image, select the View Pan tool button on the toolbar and then click on the image and drag until it is in the desired location. Panning causes the extents of the visible portion of the view to be shifted.
The iImage crop manipulator button allows you to crop your image to your specified size and dimension. It also allows you to translate and resize the crop box, and then apply the crop to the currently selected image or images. The button appears in the toolbar as shown in the following figure.
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The crop box will appear only if information has been set and is applicable to the currently-selected image. If the crop box information has not been set for the crop operation, or does not fit within your image, then no crop box appears. For more information see Cropping Images
If no crop box visual is present, you can click using the mouse anywhere on an image and drag to create a crop box.
Note All portions of the image that fall outside of the crop box are grayed out. |
Once a crop box is present, it may be translated (by clicking and dragging anywhere within the crop box, or along its edges) or scaled (by clicking and dragging on one of the scale handles). A new crop box can also be created by clicking anywhere within the gray area outside of the current crop box.
The arrow keys can also be used to translate the crop box (when the mouse location is anywhere within the crop box or along its edges).
When your crop box is correctly sized and positioned, you can crop the image by:
IDL Online Help (March 01, 2006)