Find bubble area in an image using Hough circle.

• Purpose
  This app can be used to find and characterize bubbles in an image. Bubbles are assumed to be circular. The Hough circle method is used to find the circles.
  The center and radius of circles will be output to results, together with mean radius of all circles found.
   
• Installation
  Download the file "Bubble Image Area.opx", and then drag-and-drop onto the Origin workspace. An icon will appear in the Apps gallery window.
   
• Operation
  Click the app icon from the Apps gallery window. A toolbar will pop open.
  1. Import Button: Import the image for Hough circle finding.
  2. Set Scale Button: Set scale for the image. Resize the rectangle to the actual size desired, then specify the distance, unit, and factor to set the scale.
  3. Hough Circle Button: Open the dialog for Hough circle settings and find circles for mean radius calculation.
     • Current Unit: The unit set to image.
     • Scale: Scale set to image.
     • Hough Circle Settings
       • Min Distance Between Two Circle Centers: The minimum distance between two found circle centers.
       • Min Circle Radius: The minimum circle radius to find.
       • Max Circle Radius: The maximum circle radius to find.
       • Higher Threshold to Canny Detector: The higher threshold of the two passed to the Canny edge detector (the lower one is twice smaller).
       • Accumulator Threshold for Circle Center: The accumulator threshold for the circle centers at the detection stage.
         The smaller it is, the more false circles may be detected. Circles, corresponding to the larger accumulator values, will be returned first.
       • Accumulator Resolution/Image Resolution: Inverse ratio of the accumulator resolution to the image resolution.
         For example, if =1 , the accumulator has the same resolution as the input image. If =2 , the accumulator has half as big width and height.
     • Circle Settings
       • Color: Set the of circle shows in image.
       • Line Thickness: Set the line thickness of circle shows in image.
     • Mean Radius: The average radius of all circles.
     • Init Default Button: Click this button to (re)initialize the settings for the current image
  4. Output & Close Button: If Hough circles are found, output the radius results, together with a graph marked with the circles found.

v1.2, fix bug for setting scale dialog issue in 2022
v1.1, fix bug for 4 channel image