| iTool User's Guide: Working with Images |

## Using the Image Panel

The image panel appears to the right of the visualization window of the iImage tool. This panel allows you to view and manipulate various image properties such as pixel location and values and color properties. You can also draw ROIs within your visualization. The components and functions of the image panel are discussed in the following figure and list.

Figure 10-4: The Image Panel

Figure 10-4: The Image Panel

- ROIs — The ROI buttons on the image panel allow you to draw regions of interest within your visualization. For more information on ROIs, see Image ROIs in the following section.

- Pixel Location — If your pointer/cursor is held over the visualization, the precise pixel location will be shown in this area.

- Pixel Value — Pixel color values are shown in this area.

Note If the byte scaled pixel value (used for display) is different from the image data value at that pixel, it will be displayed in parentheses.

- Pixel Scale — Pixel scale data is shown in this area.

- Edit Palette — This button is enabled for indexed binary and greyscale color images. For more information on the Palette Editor, see The Palette Editor in the following section.

- Window Level Control — The window level control allows you to adjust and manipulate the image brightness and contrast by changing the RGBA or indexed channel values. For more information on the window level control, see Window Level Control in the following section.

### Image ROIs

The ROI buttons (shown in the Image Panel in the preceding figure) allow you to draw regions of interest within your visualization. You can select from rectangular, elliptical, polygonal, and freehand region of interest buttons. Once you have created your ROI, you can also apply operations to image data contained within an ROI area.

Note The ROI tools are not available for images that have an associated map projection.

Select the desired button and then hold your cursor over the area in the visualization where you wish your ROI to appear. Click the left mouse button and drag until the ROI is the desired shape and location. ROIs can be selected and moved or deleted after they are drawn.

Note For more information on operations and regions of interest, see Operations on Regions of Interest.

### The Palette Editor

RGB images contain their own color information while color information for indexed images is separate from the image itself. Color information can be modified for indexed and greyscale images.

The easiest way to modify color attributes for a selected indexed, binary, or greyscale image is to click on the Edit Palette... button on the image panel to the right of your visualization.

The various components and functions of the Palette Editor are discussed in CW_PALETTE_EDITOR.

Note You can also access the palette editor by selecting the image visualization (clicking once on the visualization and then double-clicking on it to bring up the Visualization Browser) and selecting Image Palette Edit Color Table Edit.

### Window Level Control

The Window Level Control on the iImage tool allows you to adjust and manipulate the image brightness and contrast for each channel of the currently selected image. The Channel droplist allows you to select the channel to be adjusted. The Link All checkbox may be selected to cause all channels to be adjusted simultaneously. A small plot window shows the histogram for the currently selected channel. For indexed color images, Channel 0 represents the image data values. For RGBA images, Channel 0 represents the red values, Channel 1 represents the green values, Channel 2 the blue values, and Channel 3 the alpha values (if present). Within the plot area is a red bar representing minimum values and a green bar representing maximum values. You can click on each bar to manipulate these values. The dotted black bar represents the level; you can click and drag this bar to move both the minimum and maximum values simultaneously.

IDL Online Help (March 01, 2006)