AdaptiveStretch that’s useful when you want to achieve a stretch in a short amount of time. If the amount of processing time is important to you, consider using the EZ Soft Stretch as well – experiment to find out which works well for your image.

AdaptiveStretch maximizes contrast without clipping pixels to either 0 or 1. AdaptiveStretch has one main parameter to adjust making it easy to use. It also has a real-time preview making it easy to figure out whether AdaptiveStretch is suitable for your image.

Before you use AdaptiveStretch, your STF must be set at its default because having the STF active will affect PixInsight’s calculations.

Resetting the STF

If it is not already open, start the ScreenTransferFunction process by selecting from the menu Process – IntensityTransformations – ScreenTransferFunction or locate it under <All Processes> in the Process menu.

Do the following to reset the STF:

  1. Ensure that the Track View option is enabled (the checkmark icon at the bottom-right of the STF window)
  2. Click your image to make it the active image
  3. Click the Reset button at the bottom-right of the STF window

Using AdaptiveStretch

1. You need to have at least one image open on your PixInsight desktop

2. Start AdaptiveStretch by selecting from the menu Process – IntensityTransformations – AdaptiveStretch or find it under the <All Processes> option under the Process menu

3. Enable the Real-Time preview by clicking the open circle icon at the bottom-left of the AdaptiveStretch window

4. Adjust the exponent on the far right side of the AdaptiveStretch window on the ‘Noise Threshold’ setting until you see your image developing

5. Adjust the ‘Noise Threshold’ as desired to stretch your image

6. Optionally, enable the ‘Contrast protection’ parameter by clicking the checkbox on the far-right of the window

7. Adjust the exponent of the ‘Contrast protection’ parameter until you see desirable changes in your image

6. Once satisfied, close the RTP and drag the New Instance icon (the icon at the lower-left of the AdaptiveStretch window) to your image to execute the stretch

The Real-Time graph shows you the Curves adjustment that AdaptiveStretch is calculating and applying to your image. You can click the third icon from the bottom left of the graph window to open the graph in the CurvesTransformation window; this is just for your information and does not affect the process.

Conclusion

In this article, you learned about AdaptiveStretch, you learned what it does and learned how to use it.

More Articles In This Series

This article is part of a whole series of articles about processing images using PixInsight: