user3144987
user3144987

Reputation: 81

How can I remove blue background color on image using OpenCV?

I'm trying to remove the blue background color on below image. The blue color can be light or deep. I tried to use cv2.inRange() function but failed. How can I do that?

enter image description here

import sys
import cv2
import numpy as np

image = cv2.imread(sys.argv[1])

hsv = cv2.cvtColor(image, cv2.COLOR_BGR2HSV)

lower_blue = np.array([85, 50, 40])
upper_blue = np.array([135, 255, 255])

mask = cv2.inRange(hsv, lower_blue, upper_blue)

image[mask>0]=(255, 255, 255)

cv2.imshow('image',image)
cv2.waitKey(0)

Upvotes: 4

Views: 6128

Answers (2)

lucians
lucians

Reputation: 2269

I removed the background and also did OCR on the image. Here is the result:

result

And the code I used:

import pytesseract
import cv2

pytesseract.pytesseract.tesseract_cmd = 'C:\\Program Files (x86)\\Tesseract-OCR\\tesseract.exe'

img = cv2.imread('idText.png')

gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
adaptiveThresh = cv2.adaptiveThreshold(gray, 255, cv2.ADAPTIVE_THRESH_MEAN_C, cv2.THRESH_BINARY, 35, 90)

config = '-l eng --oem 1 --psm 3'
text = pytesseract.image_to_string(adaptiveThresh, config=config)

print("Result: " + text)

cv2.imshow('original', img)
cv2.imshow('adaptiveThresh', adaptiveThresh)

cv2.waitKey(0)

Hope I helped you.

Upvotes: 4

nathancy
nathancy

Reputation: 46600

enter image description here

You can try thresholding to obtain a binary image and morphological transformations to smooth the text

import cv2

image = cv2.imread('1.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
thresh = cv2.threshold(gray,105, 255, cv2.THRESH_BINARY_INV)[1]
thresh = 255 - thresh

kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (3,3))
result = cv2.morphologyEx(thresh, cv2.MORPH_OPEN, kernel, iterations=1)

cv2.imshow('thresh', thresh)
cv2.imshow('result', result)
cv2.imwrite('result.png', result)
cv2.waitKey()

Upvotes: 1

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