Morphological Transformations

Function

Perocess an image using morphological operations.

Sample Scenario

This Step is usually used for image pre-processing when the quality of images is not ideal and further adjustment is needed.

Apply operations such as dilation, erosion, and opening and closing to denoise, fill, etc. based on actual requirements.

Input and Output

When ClosingOperator is selected, the input and output are as shown in the figure below.

Parameter Descriptions

Parameter			Description
Morphological Transformations	DilateOperator		Dilation. It is mainly used to increase the object area and join broken parts of an object.
	ErodeOperator		Erosion. It is mainly used to remove small noises and detach two connected objects.
	OpeningOperator		Opening is another name of erosion followed by dilation. It is useful in removing noise.
	ClosingOperator		Closing is reverse of Opening, i.e., dilation followed by erosion. It is useful in closing small holes inside the foreground objects, or small black points on the object.
	Skeleton		Extract the contour of the object.
	Kernel Size		The size of the kernel, i.e., the structuring element.
	Kernel Shape	MORPH_RECT	Use a rectangular kernel.
		MORPH_CROSS	Use a crossing kernel.
		MORPH_ELLIPSE	Use an elliptical kernel.

Parameter Tuning

Morphological Transformations

Default setting: DilateOperator

Options: ClosingOperator, DilateOperator, ErodeOperator, OpeningOperator, Skeleton

Descriptions:

1. ClosingOperator: Closing is reverse of Opening, Dilation followed by Erosion. It is useful in closing small holes inside the foreground objects, or small black points on the object.

   Kernel Size

   Default setting: 21 pixel

   Instruction: The size of the kernel should be set according to the measurement requirements. The figure below shows the effect when the kernel size is set differently (smallest on the left and largest on the right).

   

   Kernel Shape

   Default setting: Rectangle (MORPH_RECT)

   Options: Rectangle (MORPH_RECT), Cross shape (MORPH_CROSS), Ellipse (MORPH_ELLIPSE)

   Instruction:

   Performance on image detail restoration: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Time required for operation: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Hint

   It is recommended to keep the default setting. However, you may configure the setting according to specific requirements.

2. DilateOperator: Dilation. It is mainly used to increase the object area and join broken parts of an object.

   Kernel Size

   Default setting: 3 pixel

   Instruction: The size of the kernel should be set according to the measurement requirements. The larger the kernel size, the more dilated the object area. The figure below shows the effect when the kernel size is set differently (smallest on the left and largest on the right).

   

   Kernel Shape

   Default setting: Rectangle (MORPH_RECT)

   Options: Rectangle (MORPH_RECT), Cross shape (MORPH_CROSS), Ellipse (MORPH_ELLIPSE)

   Instruction:

   Performance on image detail restoration: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Time required for operation: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Hint

   It is recommended to keep the default setting. However, you may configure the setting according to specific requirements.

3. ErodeOperator: Erosion. It is mainly used to remove small noises and detach two connected objects.

   Kernel Size

   Default setting: 3 pixel

   Instruction: The size of the kernel should be set according to the measurement requirements. The larger the kernel size, the greater the erosion of the object area. The figure below shows the effect when the kernel size is set differently (smallest on the left and largest on the right).

   

   Kernel Shape

   Default setting: Rectangle (MORPH_RECT)

   Options: Rectangle (MORPH_RECT), Cross shape (MORPH_CROSS), Ellipse (MORPH_ELLIPSE)

   Instruction:

   Performance on image detail restoration: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Time required for operation: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Hint

   It is recommended to keep the default setting. However, you may configure the setting according to specific requirements.

4. OpeningOperator: Opening is another name of erosion followed by dilation. It is useful in removing noise.

   Kernel Size

   Default setting: 21 pixel

   Instruction: The size of the kernel should be set according to the measurement requirements. The figure below shows the effect when the kernel size is set differently (smallest on the left and largest on the right).

   

   Kernel Shape

   Default setting: Rectangle (MORPH_RECT)

   Options: Rectangle (MORPH_RECT), Cross shape (MORPH_CROSS), Ellipse (MORPH_ELLIPSE)

   Instruction:

   Performance on image detail restoration: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Time required for operation: MORPH_RECT < MORPH_CROSS < MORPH_ELLIPSE

   Hint

   It is recommended to keep the default setting. However, you may configure the setting according to specific requirements.

5. Skeleton: Extract the contour of the object.

   The figure below shows the effect before and after the operation.