Explanation
-----------
--# Most of the material shown here is trivial (if you have any doubt, please refer to the tutorials in
- previous sections). Let's check the general structure of the C++ program:
+@add_toggle_cpp
+Most of the material shown here is trivial (if you have any doubt, please refer to the tutorials in
+previous sections). Let's check the general structure of the C++ program:
+
+@snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp main
+
+-# Load an image (can be BGR or grayscale)
+-# Create two windows (one for dilation output, the other for erosion)
+-# Create a set of two Trackbars for each operation:
+ - The first trackbar "Element" returns either **erosion_elem** or **dilation_elem**
+ - The second trackbar "Kernel size" return **erosion_size** or **dilation_size** for the
+ corresponding operation.
+-# Call once erosion and dilation to show the initial image.
+
+
+Every time we move any slider, the user's function **Erosion** or **Dilation** will be
+called and it will update the output image based on the current trackbar values.
+
+Let's analyze these two functions:
+
+#### The erosion function
+
+@snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp erosion
+
+The function that performs the *erosion* operation is @ref cv::erode . As we can see, it
+receives three arguments:
+- *src*: The source image
+- *erosion_dst*: The output image
+- *element*: This is the kernel we will use to perform the operation. If we do not
+ specify, the default is a simple `3x3` matrix. Otherwise, we can specify its
+ shape. For this, we need to use the function cv::getStructuringElement :
+ @snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp kernel
+
+ We can choose any of three shapes for our kernel:
+
+ - Rectangular box: MORPH_RECT
+ - Cross: MORPH_CROSS
+ - Ellipse: MORPH_ELLIPSE
+
+ Then, we just have to specify the size of our kernel and the *anchor point*. If not
+ specified, it is assumed to be in the center.
+
+That is all. We are ready to perform the erosion of our image.
+
+#### The dilation function
+
+The code is below. As you can see, it is completely similar to the snippet of code for **erosion**.
+Here we also have the option of defining our kernel, its anchor point and the size of the operator
+to be used.
+@snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp dilation
+@end_toggle
+
+@add_toggle_java
+Most of the material shown here is trivial (if you have any doubt, please refer to the tutorials in
+previous sections). Let's check however the general structure of the java class. There are 4 main
+parts in the java class:
+
+- the class constructor which setups the window that will be filled with window components
+- the `addComponentsToPane` method, which fills out the window
+- the `update` method, which determines what happens when the user changes any value
+- the `main` method, which is the entry point of the program
+
+In this tutorial we will focus on the `addComponentsToPane` and `update` methods. However, for completion the
+steps followed in the constructor are:
+
+-# Load an image (can be BGR or grayscale)
+-# Create a window
+-# Add various control components with `addComponentsToPane`
+-# show the window
+
+The components were added by the following method:
+
+@snippet java/tutorial_code/ImgProc/erosion_dilatation/MorphologyDemo1.java components
+
+In short we
+
+-# create a panel for the sliders
+-# create a combo box for the element types
+-# create a slider for the kernel size
+-# create a combo box for the morphology function to use (erosion or dilation)
+
+The action and state changed listeners added call at the end the `update` method which updates
+the image based on the current slider values. So every time we move any slider, the `update` method is triggered.
- - Load an image (can be BGR or grayscale)
- - Create two windows (one for dilation output, the other for erosion)
- - Create a set of two Trackbars for each operation:
- - The first trackbar "Element" returns either **erosion_elem** or **dilation_elem**
- - The second trackbar "Kernel size" return **erosion_size** or **dilation_size** for the
- corresponding operation.
- - Every time we move any slider, the user's function **Erosion** or **Dilation** will be
- called and it will update the output image based on the current trackbar values.
+#### Updating the image
- Let's analyze these two functions:
+To update the image we used the following implementation:
--# **erosion:**
- @snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp erosion
+@snippet java/tutorial_code/ImgProc/erosion_dilatation/MorphologyDemo1.java update
- - The function that performs the *erosion* operation is @ref cv::erode . As we can see, it
- receives three arguments:
- - *src*: The source image
- - *erosion_dst*: The output image
- - *element*: This is the kernel we will use to perform the operation. If we do not
- specify, the default is a simple `3x3` matrix. Otherwise, we can specify its
- shape. For this, we need to use the function cv::getStructuringElement :
- @snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp kernel
+In other words we
- We can choose any of three shapes for our kernel:
+-# get the structuring element the user chose
+-# execute the **erosion** or **dilation** function based on `doErosion`
+-# reload the image with the morphology applied
+-# repaint the frame
- - Rectangular box: MORPH_RECT
- - Cross: MORPH_CROSS
- - Ellipse: MORPH_ELLIPSE
+Let's analyze the `erode` and `dilate` methods:
- Then, we just have to specify the size of our kernel and the *anchor point*. If not
- specified, it is assumed to be in the center.
+#### The erosion method
- - That is all. We are ready to perform the erosion of our image.
-@note Additionally, there is another parameter that allows you to perform multiple erosions
-(iterations) at once. However, We haven't used it in this simple tutorial. You can check out the
-reference for more details.
+@snippet java/tutorial_code/ImgProc/erosion_dilatation/MorphologyDemo1.java erosion
--# **dilation:**
+The function that performs the *erosion* operation is @ref cv::erode . As we can see, it
+receives three arguments:
+- *src*: The source image
+- *erosion_dst*: The output image
+- *element*: This is the kernel we will use to perform the operation. For specifying the shape, we need to use
+ the function cv::getStructuringElement :
+ @snippet java/tutorial_code/ImgProc/erosion_dilatation/MorphologyDemo1.java kernel
- The code is below. As you can see, it is completely similar to the snippet of code for **erosion**.
- Here we also have the option of defining our kernel, its anchor point and the size of the operator
- to be used.
- @snippet cpp/tutorial_code/ImgProc/Morphology_1.cpp dilation
+ We can choose any of three shapes for our kernel:
+
+ - Rectangular box: CV_SHAPE_RECT
+ - Cross: CV_SHAPE_CROSS
+ - Ellipse: CV_SHAPE_ELLIPSE
+
+ Together with the shape we specify the size of our kernel and the *anchor point*. If the anchor point is not
+ specified, it is assumed to be in the center.
+
+That is all. We are ready to perform the erosion of our image.
+
+#### The dilation function
+
+The code is below. As you can see, it is completely similar to the snippet of code for **erosion**.
+Here we also have the option of defining our kernel, its anchor point and the size of the operator
+to be used.
+@snippet java/tutorial_code/ImgProc/erosion_dilatation/MorphologyDemo1.java dilation
+@end_toggle
+
+@add_toggle_python
+Most of the material shown here is trivial (if you have any doubt, please refer to the tutorials in
+previous sections). Let's check the general structure of the python script:
+
+@snippet python/tutorial_code/imgProc/erosion_dilatation/morphology_1.py main
+
+-# Load an image (can be BGR or grayscale)
+-# Create two windows (one for erosion output, the other for dilation) with a set of trackbars each
+ - The first trackbar "Element" returns the value for the morphological type that will be mapped
+ (1 = rectangle, 2 = cross, 3 = ellipse)
+ - The second trackbar "Kernel size" returns the size of the element for the
+ corresponding operation
+-# Call once erosion and dilation to show the initial image
+
+Every time we move any slider, the user's function **erosion** or **dilation** will be
+called and it will update the output image based on the current trackbar values.
+
+Let's analyze these two functions:
+
+#### The erosion function
+
+@snippet python/tutorial_code/imgProc/erosion_dilatation/morphology_1.py erosion
+
+The function that performs the *erosion* operation is @ref cv::erode . As we can see, it
+receives two arguments and returns the processed image:
+- *src*: The source image
+- *element*: The kernel we will use to perform the operation. We can specify its
+ shape by using the function cv::getStructuringElement :
+ @snippet python/tutorial_code/imgProc/erosion_dilatation/morphology_1.py kernel
+
+ We can choose any of three shapes for our kernel:
+
+ - Rectangular box: MORPH_RECT
+ - Cross: MORPH_CROSS
+ - Ellipse: MORPH_ELLIPSE
+
+Then, we just have to specify the size of our kernel and the *anchor point*. If the anchor point not
+specified, it is assumed to be in the center.
+
+That is all. We are ready to perform the erosion of our image.
+
+#### The dilation function
+
+The code is below. As you can see, it is completely similar to the snippet of code for **erosion**.
+Here we also have the option of defining our kernel, its anchor point and the size of the operator
+to be used.
+
+@snippet python/tutorial_code/imgProc/erosion_dilatation/morphology_1.py dilation
+@end_toggle
+
+@note Additionally, there are further parameters that allow you to perform multiple erosions/dilations
+(iterations) at once and also set the border type and value. However, We haven't used those
+in this simple tutorial. You can check out the reference for more details.
Results
-------
-Compile the code above and execute it with an image as argument. For instance, using this image:
+Compile the code above and execute it (or run the script if using python) with an image as argument.
+If you do not provide an image as argument the default sample image
+([LinuxLogo.jpg](https://github.com/opencv/opencv/tree/master/samples/data/LinuxLogo.jpg)) will be used.
+
+For instance, using this image:
iterations.
+(depending on the programming language the output might vary a little or be only 1 window)
import numpy as np
import argparse
+src = None
erosion_size = 0
max_elem = 2
max_kernel_size = 21
-title_trackbar_element_type = 'Element:\n 0: Rect \n 1: Cross \n 2: Ellipse'
+title_trackbar_element_shape = 'Element:\n 0: Rect \n 1: Cross \n 2: Ellipse'
title_trackbar_kernel_size = 'Kernel size:\n 2n +1'
title_erosion_window = 'Erosion Demo'
-title_dilatation_window = 'Dilation Demo'
+title_dilation_window = 'Dilation Demo'
+
+## [main]
+def main(image):
+ global src
+ src = cv.imread(cv.samples.findFile(image))
+ if src is None:
+ print('Could not open or find the image: ', image)
+ exit(0)
+
+ cv.namedWindow(title_erosion_window)
+ cv.createTrackbar(title_trackbar_element_shape, title_erosion_window, 0, max_elem, erosion)
+ cv.createTrackbar(title_trackbar_kernel_size, title_erosion_window, 0, max_kernel_size, erosion)
+
+ cv.namedWindow(title_dilation_window)
+ cv.createTrackbar(title_trackbar_element_shape, title_dilation_window, 0, max_elem, dilatation)
+ cv.createTrackbar(title_trackbar_kernel_size, title_dilation_window, 0, max_kernel_size, dilatation)
+
+ erosion(0)
+ dilatation(0)
+ cv.waitKey()
+## [main]
+
+# optional mapping of values with morphological shapes
+def morph_shape(val):
+ if val == 0:
+ return cv.MORPH_RECT
+ elif val == 1:
+ return cv.MORPH_CROSS
+ elif val == 2:
+ return cv.MORPH_ELLIPSE
+
+
+## [erosion]
def erosion(val):
erosion_size = cv.getTrackbarPos(title_trackbar_kernel_size, title_erosion_window)
- erosion_type = 0
- val_type = cv.getTrackbarPos(title_trackbar_element_type, title_erosion_window)
- if val_type == 0:
- erosion_type = cv.MORPH_RECT
- elif val_type == 1:
- erosion_type = cv.MORPH_CROSS
- elif val_type == 2:
- erosion_type = cv.MORPH_ELLIPSE
-
- element = cv.getStructuringElement(erosion_type, (2*erosion_size + 1, 2*erosion_size+1), (erosion_size, erosion_size))
+ erosion_shape = morph_shape(cv.getTrackbarPos(title_trackbar_element_shape, title_erosion_window))
+
+ ## [kernel]
+ element = cv.getStructuringElement(erosion_shape, (2 * erosion_size + 1, 2 * erosion_size + 1),
+ (erosion_size, erosion_size))
+ ## [kernel]
erosion_dst = cv.erode(src, element)
cv.imshow(title_erosion_window, erosion_dst)
+## [erosion]
-def dilatation(val):
- dilatation_size = cv.getTrackbarPos(title_trackbar_kernel_size, title_dilatation_window)
- dilatation_type = 0
- val_type = cv.getTrackbarPos(title_trackbar_element_type, title_dilatation_window)
- if val_type == 0:
- dilatation_type = cv.MORPH_RECT
- elif val_type == 1:
- dilatation_type = cv.MORPH_CROSS
- elif val_type == 2:
- dilatation_type = cv.MORPH_ELLIPSE
-
- element = cv.getStructuringElement(dilatation_type, (2*dilatation_size + 1, 2*dilatation_size+1), (dilatation_size, dilatation_size))
- dilatation_dst = cv.dilate(src, element)
- cv.imshow(title_dilatation_window, dilatation_dst)
-parser = argparse.ArgumentParser(description='Code for Eroding and Dilating tutorial.')
-parser.add_argument('--input', help='Path to input image.', default='LinuxLogo.jpg')
-args = parser.parse_args()
+## [dilation]
+def dilatation(val):
+ dilatation_size = cv.getTrackbarPos(title_trackbar_kernel_size, title_dilation_window)
+ dilation_shape = morph_shape(cv.getTrackbarPos(title_trackbar_element_shape, title_dilation_window))
-src = cv.imread(cv.samples.findFile(args.input))
-if src is None:
- print('Could not open or find the image: ', args.input)
- exit(0)
+ element = cv.getStructuringElement(dilation_shape, (2 * dilatation_size + 1, 2 * dilatation_size + 1),
+ (dilatation_size, dilatation_size))
+ dilatation_dst = cv.dilate(src, element)
+ cv.imshow(title_dilation_window, dilatation_dst)
+## [dilation]
-cv.namedWindow(title_erosion_window)
-cv.createTrackbar(title_trackbar_element_type, title_erosion_window , 0, max_elem, erosion)
-cv.createTrackbar(title_trackbar_kernel_size, title_erosion_window , 0, max_kernel_size, erosion)
-cv.namedWindow(title_dilatation_window)
-cv.createTrackbar(title_trackbar_element_type, title_dilatation_window , 0, max_elem, dilatation)
-cv.createTrackbar(title_trackbar_kernel_size, title_dilatation_window , 0, max_kernel_size, dilatation)
+if __name__ == "__main__":
+ parser = argparse.ArgumentParser(description='Code for Eroding and Dilating tutorial.')
+ parser.add_argument('--input', help='Path to input image.', default='LinuxLogo.jpg')
+ args = parser.parse_args()
-erosion(0)
-dilatation(0)
-cv.waitKey()
+ main(args.input)
projects / platform / upstream / opencv.git / commitdiff