Advanced Display

The Advanced Display ribbon provides controls that allow you to improve the visualization of images in the following ways:

  • Display Range:  Often images are captured such that the actual useful data does not cover very much of the dynamic range of the image. For example, the dynamic range of an 8-bit image is 0-255, but the useful data in an image may cover only a small portion of that range (such as 50-200).  The display range controls allow you to set the Black and White levels such that all pixel intensities below the black level display as black and all pixel intensities above the white level display as white.  All intensities within the active range are scaled to the 0-255 range.  Setting the Black and White levels can be very useful to exclude irrelevant image data and/or boost the contrast between relevant intensities.
  • Brightness, Contrast, and Gamma: These are standard image adjustment controls that allow you to uniformly increase or decrease the brightness and contrast in images.  

When the Advanced Display controls are adjusted, the pixel values in your image bitmap are not actually modified; the controls modify a Lookup Table (LUT) through which your image is interpreted. For example, when you increase brightness in an image, all of the intensity values in your image are increased by a certain amount.  The pixel values in your image are not actually changed; the changes you see on the screen are calculated by reading the image's original value and processing it through the Lookup Table.

Image-Pro uses an LUT for processing intensity enhancements because:

  • It is the fastest way to apply multiple adjustments to an image, and
  • It lets you easily reverse adjustments you have made.

When contrast modifications are performed, all changes are placed into the LUT. If you were to copy, resize or otherwise perform an operation that produces a new window from your bitmap, the results would be derived from the unenhanced values.

To make the LUT enhancements permanent, you must click the Apply button on the Advanced Display ribbon or the Adjust ribbon.  If an ROI is active when the Apply option is performed, the LUT values will be written to just the pixels within the ROI.

When the Advanced Display ribbon is displayed, the Advanced Display panel appears at the bottom of the application window. This panel displays a histogram of intensity values in the image.  The histogram display indicates the current black and white levels with markers, which can be moved by clicking and dragging the marker to a new value. The image display automatically updates to indicate the effects as the level is changed.

See Advanced Display Window for more information.