Threshold a Grayscale Image

NI Vision Assistant

Threshold a Grayscale Image

Main Tab

In the Step Name control, enter a descriptive name for the step.

Threshold Tab

  1. Select whether you want the function to look for bright, dark, or gray objects.
  2. Select the type of threshold you want to perform.
Note  You cannot adjust the threshold levels of the local and automatic thresholds. If none of the local or automatic thresholding options work for the image, select Manual Threshold and adjust the pointers on the histogram until all of the particles of interest are highlighted in red.
  1. Click OK to threshold the image and add this step to the script.
Tips  
  • If you have trouble finding a manual threshold range that selects all of the pixels in the range, draw an ROI around the portion of the image that you want to keep. The histogram displays the intensities of the ROI only. Use the minimum and maximum values for the threshold.