[FIXED] Tesseract-OCR not recognizing multiple characters in a single image

Issue

Im a beginner in Tesseract-OCR and I am doing this project in Python to recognize multiple separated characters in one image. I looked up the documentation for PyTesseract and I could not find any reference for detecting multiple characters in different positions.

I tried changing the configurations but I still cannot detect any characters. My idea is to scan the available characters on the image, print their bounding boxes and find the center of each bounding box, print out the character's rotation in degrees.

Can anyone help me? Thanks.

Solution

Maybe this is what you mean.

import cv2
import numpy as np
import pytesseract
import imutils

img = cv2.imread("srj8n.png")
cv2.imshow("original", img)

# turn into gray for next processing
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)


thresh = cv2.threshold(gray, 0, 255, cv2.THRESH_BINARY_INV * cv2.THRESH_OTSU)[1]
thresh = cv2.bitwise_not(thresh)

# omit the underline
kernel = np.ones((4, 4), np.uint8)
erosion = cv2.erode(thresh, kernel, iterations=1)

# dilate to make the line thicker
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (9, 12))
dilation = cv2.dilate(erosion, kernel, iterations=1)

# find the contour
cntrs = cv2.findContours(dilation, cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_SIMPLE)
cntrs = cntrs[0] if len(cntrs) == 2 else cntrs[1]

result = img.copy()
for c in cntrs:
    # for each letter, create red rectangle
    x, y, w, h = cv2.boundingRect(c)
    cv2.rectangle(result, (x, y), (x + w, y + h), (0, 0, 255), 2)

    # prepare letter for OCR
    box = thresh[y:y + h - 2, x:x + w]
    box = cv2.bitwise_not(box)
    box = cv2.GaussianBlur(box, (3, 3), 0)

    # retreive the angle. For the meaning of angle, see below
    # https://namkeenman.wordpress.com/2015/12/18/open-cv-determine-angle-of-rotatedrect-minarearect/
    rect = cv2.minAreaRect(c)
    angle = rect[2]

    # put angle below letter
    font = cv2.FONT_HERSHEY_SIMPLEX
    bottomLeftCornerOfText = (x, y+h+20)
    fontScale = 0.6
    fontColor = (255, 0, 0)
    lineType = 2
    cv2.putText(result, str(angle), bottomLeftCornerOfText, font, fontScale, fontColor, lineType)

    # do the OCR
    custom_config = r'-l eng --oem 3 --psm 10'
    text = pytesseract.image_to_string(box, config=custom_config)
    print("Detected :" + text + ", angle: " + str(angle))

cv2.imshow("result", result)

cv2.waitKey(0)
cv2.destroyAllWindows()

Answered By - us2018