I have a number of blueprints where I would like to detect the numbers on the blueprint such that I can turn them into proper models. for example I have the following image
and would like all the numbers on this image so I ran the following code:
import pytesseract
from pytesseract import Output
import cv2
import numpy as np
img = cv2.imread('vdb7C.jpg')
custom_config = r' (--oem 2 --psm 10'
d = pytesseract.image_to_data(img,config=custom_config,lang='eng', output_type=Output.DICT)
n_boxes = len(d['level'])
for i in range(n_boxes):
text=d["text"][i]
print(text+ str(str.isdigit(text)))
if str.isdigit(text):
(x, y, w, h) = (d['left'][i], d['top'][i], d['width'][i], d['height'][i])
cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
cv2.imwrite("output.jpg" , img)
This gave me the following result:
. As you can see it does correctly identify a number of numbers on the blueprint, however it misses quite a few others and falsely detect a few that aren't really there. I care more about getting all the numbers than a few false positives but would still like to keep those to a minimum so any suggestions there?
I have already tried thinning operations, re-scaling the images, rotating the images and smoothing the images but all of those don't appear to make much difference, extreme rescaling (*0.1 or *10) does change a few things but any gains made in one part of the image are undone by faults appearing in other parts.
Especially difficult are situations such as on the left building where we have lines numbers close to or even overlapping part of the design.
Here we see 2 examples of such situations

It's worth noting that the lines are almost always obviously thinner then the fond used for the numbers so perhaps something could be done with that?
I have also tried using the EAST OCR system with the following code: img = cv2.imread('vdb7C.jpg')
W=5664
H=4000
dim = (W, H)
img = cv2.resize(img, dim, interpolation = cv2.INTER_AREA)
net = cv2.dnn.readNet("frozen_east_text_detection.pb")
blob = cv2.dnn.blobFromImage(img, 1.0, (W, H),
(123.68, 116.78, 103.94), swapRB=True, crop=False)
net.setInput(blob)
(scores, geometry) = net.forward(["feature_fusion/Conv_7/Sigmoid",
"feature_fusion/concat_3"])
(numRows, numCols) = scores.shape[2:4]
rects = []
confidences = []
# loop over the number of rows
for y in range(0, numRows):
# extract the scores (probabilities), followed by the geometrical
# data used to derive potential bounding box coordinates that
# surround text
scoresData = scores[0, 0, y]
xData0 = geometry[0, 0, y]
xData1 = geometry[0, 1, y]
xData2 = geometry[0, 2, y]
xData3 = geometry[0, 3, y]
anglesData = geometry[0, 4, y]
for x in range(0, numCols):
if scoresData[x] < confidence:
continue
(offsetX, offsetY) = (x * 4.0, y * 4.0)
angle = anglesData[x]
cos = np.cos(angle)
sin = np.sin(angle)
h = xData0[x] + xData2[x]
w = xData1[x] + xData3[x]
endX = int(offsetX + (cos * xData1[x]) + (sin * xData2[x]))
endY = int(offsetY - (sin * xData1[x]) + (cos * xData2[x]))
startX = int(endX - w)
startY = int(endY - h)
rects.append((startX, startY, endX, endY))
confidences.append(scoresData[x])
boxes = non_max_suppression(np.array(rects), probs=confidences)
for box in boxes:
(y,h,x,w) = box
print(box)
print(np.shape(img))
cv2.rectangle(img, (x, y), (x + w, y + h), (0, 255, 0), 2)
cv2.imwrite("output.jpg" , img)
however this causes quite a number of bounding boxes to be outside of the image and in general the bounding boxes seem unrelated to the content, so anyone know what's up there? Any suggestions?
from How do I improve the number detection for blueprints (OCR)
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