Show – The Display Window

Show creates a window in which its input image is displayed. This page describes the controls in that window.

Each window is named “Image N-title”. N counts the images displayed so far, and the title is the one set in the Show arguments (“Untitled” by default).

• Choose the image's name from the Images menu to bring its window to the front. See Images menu.
• Select Next or Previous to bring forward the next or previous displayed image.

Turn the mouse's scroll wheel to zoom in or out, and drag with the left mouse button to move the image. To compare several images, link them; see Linked Images.

For multiband images, use the band slider; see Displaying the Bands.

Hold down Shift and drag with the left mouse button to draw a window on the image. Select Save to copy its coordinates to the clipboard and add it to the Windows menu. See Window Arguments.

Right-click inside a window for two more tools:

• Histogram shows up to 3 histograms of the data inside the window.
• Spectrum plots the average value of each band inside the window.

For a three-band, 8-bit color image, a panel at the bottom of the window lets you adjust the brightness, contrast, saturation and hue angle with sliders, and see the result in the image. When you are satisfied, select Copy to copy the adjustments to the clipboard. You can paste them into the “command” entry of the TRC module (Intermediate level), which applies them to the image it receives.

For a single-band image, an enhancement panel appears at the bottom of the window:

• Pack (the default) stretches the values linearly over 3 standard deviations (sigmas) around the mean.
• Linear stretches the values linearly between the minimum and maximum.
• Equalize uses the histogram of the image, favoring the most frequently occurring values.
• Gray shows the image in grayscale. Jet or Parula show it in color with that colormap.
• Two sliders set the minimum and maximum values used by all the adjustments. Copy puts these two values on the clipboard, so you can paste them into the “min-max” box of Pack, which offers the same adjustments.