Blob Detection - ( Drawing and Image Processing in OpenCV )

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Syntax

cv2.SimpleBlobDetector_create([params])

Example

import cv2
import numpy as np

# read image in grayscale
img = cv2.imread('image.jpg', cv2.IMREAD_GRAYSCALE)

# create blob detector object
detector = cv2.SimpleBlobDetector_create()

# detect blobs in the image
keypoints = detector.detect(img)

# draw detected blobs on the image
img_with_blobs = cv2.drawKeypoints(img, keypoints, np.array([]), (0, 0, 255), cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)

# show the image with detected blobs
cv2.imshow('Blobs', img_with_blobs)
cv2.waitKey(0)
cv2.destroyAllWindows()

Output

The output will be an image with the detected blobs highlighted.

Explanation

Blob detection is a technique used to identify regions of an image that differ in properties, such as brightness or color, from surrounding regions. OpenCV provides a simple blob detector that can be used to perform blob detection on grayscale images.

In the above example, we read an image in grayscale and create a blob detector object using cv2.SimpleBlobDetector_create(). We then use the detector.detect() function to detect blobs in the image. Finally, we use the cv2.drawKeypoints() function to draw the detected blobs on the image.

Use

Blob detection can be used in various computer vision applications, such as object recognition, tracking, and segmentation. It can also be used in image processing to identify regions of interest in an image.

Important Points

• Blob detection is a technique used to identify regions of an image that differ in properties from surrounding regions
• OpenCV provides a simple blob detector that can be used to perform blob detection on grayscale images
• The cv2.SimpleBlobDetector_create() function creates a blob detector object
• The detector.detect() function is used to detect blobs in the image
• The cv2.drawKeypoints() function is used to draw the detected blobs on the image

Summary

In conclusion, blob detection is a useful technique in computer vision and image processing for identifying regions of interest in an image. OpenCV provides a simple blob detector that can be used to perform blob detection on grayscale images. The cv2.SimpleBlobDetector_create() function creates a blob detector object, while the detector.detect() function is used to detect blobs in the image. Finally, the cv2.drawKeypoints() function is used to draw the detected blobs on the image.