Performing multiscale segmentation using SLIC (Simple Linear Iterative Clustering) and merging the results efficiently involves several steps. Below is a step-by-step guide to achieve this, including the definition of the merge_mean_color
function.
Step 1: Install Required Libraries
First, ensure you have the necessary libraries installed. You will need scikit-image
for SLIC and numpy
for numerical operations.
pip install scikit-image numpy
Step 2: Import Libraries
import numpy as np
from skimage import io, segmentation, color
from skimage.future import graph
Step 3: Define the merge_mean_color
Function
The merge_mean_color
function will be used to merge regions based on their mean color.
def merge_mean_color(graph, src, dst, n):
"""Callback to handle merging nodes by recomputing mean color."""
graph.nodes[dst]['total color'] += graph.nodes[src]['total color']
graph.nodes[dst]['pixel count'] += graph.nodes[src]['pixel count']
graph.nodes[dst]['mean color'] = (graph.nodes[dst]['total color'] /
graph.nodes[dst]['pixel count'])
Step 4: Perform Multiscale Segmentation Using SLIC
You can perform SLIC segmentation at different scales by varying the n_segments
parameter.
def slic_multiscale(image, scales):
segments_list = []
for scale in scales:
segments = segmentation.slic(image, n_segments=scale, compactness=10, start_label=1)
segments_list.append(segments)
return segments_list
Step 5: Merge Multiscale Segmentation Results
To merge the results efficiently, you can use the merge_hierarchical
function from skimage.future.graph
.
def merge_segments(image, segments_list):
merged_segments = segments_list[0]
for segments in segments_list[1:]:
rag = graph.rag_mean_color(image, segments)
merged_segments = graph.merge_hierarchical(segments, rag, thresh=35, rag_copy=False,
in_place_merge=True,
merge_func=merge_mean_color,
weight_func=graph.rag_mean_color)
return merged_segments
Step 6: Putting It All Together
Here is the complete code to perform multiscale segmentation and merge the results:
import numpy as np
from skimage import io, segmentation, color
from skimage.future import graph
def merge_mean_color(graph, src, dst, n):
"""Callback to handle merging nodes by recomputing mean color."""
graph.nodes[dst]['total color'] += graph.nodes[src]['total color']
graph.nodes[dst]['pixel count'] += graph.nodes[src]['pixel count']
graph.nodes[dst]['mean color'] = (graph.nodes[dst]['total color'] /
graph.nodes[dst]['pixel count'])
def slic_multiscale(image, scales):
segments_list = []
for scale in scales:
segments = segmentation.slic(image, n_segments=scale, compactness=10, start_label=1)
segments_list.append(segments)
return segments_list
def merge_segments(image, segments_list):
merged_segments = segments_list[0]
for segments in segments_list[1:]:
rag = graph.rag_mean_color(image, segments)
merged_segments = graph.merge_hierarchical(segments, rag, thresh=35, rag_copy=False,
in_place_merge=True,
merge_func=merge_mean_color,
weight_func=graph.rag_mean_color)
return merged_segments
# Load your image
image = io.imread('path_to_your_image.jpg')
# Define scales for multiscale segmentation
scales = [100, 200, 300]
# Perform multiscale segmentation
segments_list = slic_multiscale(image, scales)
# Merge the segmentation results
merged_segments = merge_segments(image, segments_list)
# Visualize the result
out = color.label2rgb(merged_segments, image, kind='avg')
io.imshow(out)
io.show()
Explanation:
merge_mean_color
Function: This function updates the mean color of the merged regions.
slic_multiscale
Function: This function performs SLIC segmentation at different scales.
merge_segments
Function: This function merges the segmentation results using a region adjacency graph (RAG) and hierarchical merging.
- Main Code: Load the image, define scales, perform multiscale segmentation, merge the results, and visualize the final segmentation.
This approach ensures that the segmentation results from different scales are efficiently merged to produce a coherent final segmentation.