convert to module layout

_modules/filter_morphological.md

 ---
-title:     Morphological filters
-layout:    page
-permalink: /filtermorphological
+title:     Morphological Filters
+layout:    module
+prerequisites:
+  - "[Neighbourhood filters](filter_neighbourhood)"
+  - "[Rank filters](filter_rank)"
+objectives:
+  - "Design morphological filters using rank filters"
+  - "Execute morphological filters on binary or grayscale images and explain the output"
+motivation: >
+  Filters can be used to change size and shape of objects in an image. [*] Concept map below assumes bright objects on dark background. For dark objects on bright background effect of min and max filters is inverted.
+concept_map: >
+  graph TD
+      image --> max1[max]
+      image --> min1[min]
+      image --> max2[max]
+      image --> min2[min]
+      image --> d
+  subgraph rank filter sequence
+      max2 --> min3[min]
+      min2 --> max3[max]
+      max1
+      min1
+      d[max - min]
+      end
+      max1 --> dilation
+      min1 --> erosion
+      max3 --> opening
+      min3 --> closing
+      d --> gradient
+      subgraph morphological filter name
+      dilation
+      erosion
+      opening
+      closing
+      gradient
+      end
+
+# figure: TODO
+# figure_legend: TODO
+
+activity_preface: >
+  Open the image, `xy_8bit_binary_two_spots_different_size.tif`, and explore how structures grow and shrink, using erosion and dilation
+
+# activities:
+#   "Platform": "path/to/file.md"
+
+exercises_preface: >
+
+  ### Exercise 1
+
+  Fill in the blanks, using those words: "shrinks", "increases", "decreases", "enlarges".
+
+  1. An erosion _____ objects in a binary image.
+  2. An erosion in a binary image _____ the number of foreground pixels.
+  3. A dilation in a grayscale image _____ the average intensity in the image.
+  4. A dilation _____ objects in a binary image.
+
+
+  ### Exercise 2
+
+  True of false? Discuss with your neighbour!
+
+  1. Morphological openings on binary images can decrease the number of foreground pixels.
+  2. Morphological closings on binary images never decreases the number of foreground pixels.
+  3. Performing a morphological closing a twice in a row does not make sense, because the second closing does not further change the image.
+
+# exercises:
+#   "Platform": "path/to/file.md"
+
+learn_next:
+  - TODO
+
+external_links:
+  - "[Wikipedia: Morphological Gradient](https://en.wikipedia.org/wiki/Morphological_gradient)"
+  - "[ImageJ docs: Greyscale morphological filters](https://imagej.net/MorphoLibJ#Grayscale_morphological_filters)"
 ---
-
-# Morphological filters
-
-## Requirements
-
-- Neighbourhood filters
-- Rank filters
-
-## Motivation
-
-This module explains how filters can be used to change size and shape of objects in the image.
-
-## Learning objectives
-- Understand how to design morphological filters using rank filters
-- Execute morpholofical filters on binary or grayscale images and explain the output
-
-## Concept map
-```mermaid
-graph TD
-    image --> max1[max]
-    image --> min1[min]
-    image --> max2[max]
-    image --> min2[min]
-    image --> d 
-subgraph rank filter sequence
-    max2 --> min3[min]
-    min2 --> max3[max]
-    max1
-    min1
-    d[max - min]
-    end
-    max1 --> dilation
-    min1 --> erosion
-    max3 --> opening
-    min3 --> closing
-    d --> gradient
-    subgraph morphological filter name
-    dilation
-    erosion
-    opening
-    closing
-    gradient
-    end
-```
-
-[*] Concept map above assumes bright objects on dark background. For dark objects on bright background effect of min and max filters inverses 
-
-### Activity: Explore erosion and dilation on binary images
-
-- Open image: xy_8bit_binary__two_spots_different_size.tif
-- Explore how structures grow and shrink, using erosion and dilation
-
-### Activity: Explore opening and closing on binary images
-
-- Open image: xy_8bit_binary__for_open_and_close.tif
-- Explore effects of morphological closing and opening:
-	- closing can fill holes
-	- closing can connect gaps
-	- opening can remove thin structures
-
-### Formative assessment
-
-Fill in the blanks, using those words: shrinks, increases, decreases, enlarges.
-
-1. An erosion _____ objects in a binary image. 
-2. An erosion in a binary image _____ the number of foreground pixels.
-3. A dilation in a grayscale image _____ the average intensity in the image.
-4. A dilation _____ objects in a binary image.
-
-
-True of false? Discuss with your neighbour!
-
-1. Morphological openings on binary images can decrease the number of foreground pixels.
-2. Morphological closings on binary images never decreases the number of foreground pixels.
-3. Performing a morphological closing a twice in a row does not make sense, because the second closing does not further change the image.
-
-## Learn more
-
-- https://en.wikipedia.org/wiki/Morphological_gradient
-- https://imagej.net/MorphoLibJ#Grayscale_morphological_filters