Region Growing

 

In this mode, you can threshold a specific region of the image.

 

You must first select a threshold range with the Upper and Lower limit tools. You can then precisely Tag all the pixels that fall within this range with a paint brush (Paint mode) or grow a 2D or 3D region using the pixels under the brush as a seed.

 

 

From the Graphic Interface

 

          

 

Brush

 

Select the brush used to paint in the Display Area. This tool is also described in the "Interface tools" section of the introduction

TAG Value

Select the current Tag value. This tool is also described in the "Interface tools" section of the introduction

 

Paint button

A left click on the mouse will activate the brush. All the pixels under the brush whose GLI values are within the threshold range will be tagged. The right mouse button is used to “erase” to modification and bring back the Tag values from the last “load” operation.

 

Grow 2D button

A left click on the mouse will seed a region under the cursor. In order to grow, the region must meet the following criteria: 

The GLI values of the pixels must be  within the threshold range.

The region will not grow through a region smaller than the radius of the brush.

Depending on the value of the $REGION_OVERWRITE variable, The region will not overwrite a a pixel whose TAG value is:

($REGION_OVERWRITE=4) Smaller than the current Tag value.

($REGION_OVERWRITE=5) Smaller or equal than the current Tag value.

($REGION_OVERWRITE=1) equal to the current Tag value.

($REGION_OVERWRITE=3) Superior or equal to the current Tag value (Default value).

($REGION_OVERWRITE=2) Superiorl to the current Tag value.

The right mouse button can be used to erase the latest grow operation.

 

Grow 3D button

A left click on the mouse will seed a 3D region under the cursor. The flood will propagate through all the frames that belong to the same parent. In order to grow, the region must meet the following criteria: 

The GLI values of the pixels must be  within the threshold range.

The region will not grow through a region smaller than the radius of the brush.

Depending on the value of the $REGION_OVERWRITE variable, The region will not overwrite a a pixel whose TAG value is:

($REGION_OVERWRITE=4) Smaller than the current Tag value.

($REGION_OVERWRITE=5) Smaller or equal than the current Tag value.

($REGION_OVERWRITE=1) equal to the current Tag value.

($REGION_OVERWRITE=3) Superior or equal to the current Tag value (Default value).

($REGION_OVERWRITE=2) Superiorl to the current Tag value.

The right mouse button can be used to erase the latest grow operation.

 

Histogram box

Displays the histogram of the grey values of the GLI image(s). The vertical axis represents the number of pixels having a particular value, while the horizontal axis represents the possible values of the pixels (from Minimum at left to Maximum at right). The threshold range fixed by the lower and upper limits will be superimposed on this histogram. When the cursor is over an image, the GLI value of the pixel under the cursor is indicated by a white vertical bar on the histogram. This tool is also described in the "Interface tools" section of the introduction

 

Lower limit button

Activates and control the lower limit slider.

“Off”: the upper limit is disabled. 

"On": the Upper limit slider directly fixes the minimum GLI value that a pixel can have in order to be within the threshold range for painting or growing.

 

Lower limit slider

Give the value that is used to form the lower limit of the threshold range. This slider can be locked in position by pressing the “Scroll Lock” key while the cursor is over it.

 

Upper limit button

Activates and control the upper limit slider.

“Off”: the upper limit is disabled. 

"On": the Upper limit slider directly fixes the maximum GLI value that a pixel can have in order to be within the threshold range for painting or growing.

 

Upper limit slider

Gives the value that is used to form the upper limit of the threshold range. This slider can be locked in position by pressing the “Scroll Lock” key while the cursor is over it.

 

Preview

If ON, a preview of the segmentation will be displayed in Paint and Grow 2D modes.

 

Preview color

This slider enables you to change the preview’s color to make it more visible. An example of the current color is showed in the box at the right of the slider.

Note:

The preview is unavailable in the Grow_3D sub-mode

 

Mouse wheel

You can use the mouse wheel to change the threshold values. You can select which of the thresholds will be affected by the mouse wheel, or disable the mouse wheel control.

 

Load

Manually load the image in the restore buffer. See Undo/Redo in the Main Menu section for more information on the Load and Erase functions

 

Undo

Undo last brush stroke. It is a shortcut to the “Undo” button of the Uno/Redo Menu. It can only undo “Region Growing” operations.

 

Propagate

Propagate the Region Growing to an adjacent frame. This tool is also described in the "Interface tools" section of the introduction

 

 

From the Display Area

 

The mouse controls associated with this mode are:

 

For the “Paint” sub-mode

 



 

Mouse button

Function

 



 

Left

Threshold the regions under the cursor.

 

Right

Restore the tag values in all the regions under the cursor.

 

Middle

Increase the brush to a big square, allowing to threshold  or restore a larger surface.

 

Wheel

Increase/decrease the select threshold value

 

 

For the “Grow 2D” and “Grow 3D” sub-mode

 



 

Mouse button

Function

 



 

Left

Grow a region starting at the current cursor position.

 

Right

Grow a region starting at the current cursor position.

 

Middle

Increase the brush to a big square

 

Wheel

Increase/decrease the select threshold value

 

 

From the Keyboard

 

There is no keyboard interface specific to this mode.

 

 

From the Command Line

 

A list of the commands available while in this mode can be found in the "SliceO_TAG\Region.dll" section of appendix B.