opencv/samples/dnn/text_detection.py

240 lines
9.1 KiB
Python

'''
Text detection model: https://github.com/argman/EAST
Download link: https://www.dropbox.com/s/r2ingd0l3zt8hxs/frozen_east_text_detection.tar.gz?dl=1
CRNN Text recognition model taken from here: https://github.com/meijieru/crnn.pytorch
How to convert from pb to onnx:
Using classes from here: https://github.com/meijieru/crnn.pytorch/blob/master/models/crnn.py
More converted onnx text recognition models can be downloaded directly here:
Download link: https://drive.google.com/drive/folders/1cTbQ3nuZG-EKWak6emD_s8_hHXWz7lAr?usp=sharing
And these models taken from here:https://github.com/clovaai/deep-text-recognition-benchmark
import torch
from models.crnn import CRNN
model = CRNN(32, 1, 37, 256)
model.load_state_dict(torch.load('crnn.pth'))
dummy_input = torch.randn(1, 1, 32, 100)
torch.onnx.export(model, dummy_input, "crnn.onnx", verbose=True)
'''
# Import required modules
import numpy as np
import cv2 as cv
import math
import argparse
############ Add argument parser for command line arguments ############
parser = argparse.ArgumentParser(
description="Use this script to run TensorFlow implementation (https://github.com/argman/EAST) of "
"EAST: An Efficient and Accurate Scene Text Detector (https://arxiv.org/abs/1704.03155v2)"
"The OCR model can be obtained from converting the pretrained CRNN model to .onnx format from the github repository https://github.com/meijieru/crnn.pytorch"
"Or you can download trained OCR model directly from https://drive.google.com/drive/folders/1cTbQ3nuZG-EKWak6emD_s8_hHXWz7lAr?usp=sharing")
parser.add_argument('--input',
help='Path to input image or video file. Skip this argument to capture frames from a camera.')
parser.add_argument('--model', '-m', required=True,
help='Path to a binary .pb file contains trained detector network.')
parser.add_argument('--ocr', default="crnn.onnx",
help="Path to a binary .pb or .onnx file contains trained recognition network", )
parser.add_argument('--width', type=int, default=320,
help='Preprocess input image by resizing to a specific width. It should be multiple by 32.')
parser.add_argument('--height', type=int, default=320,
help='Preprocess input image by resizing to a specific height. It should be multiple by 32.')
parser.add_argument('--thr', type=float, default=0.5,
help='Confidence threshold.')
parser.add_argument('--nms', type=float, default=0.4,
help='Non-maximum suppression threshold.')
args = parser.parse_args()
############ Utility functions ############
def fourPointsTransform(frame, vertices):
vertices = np.asarray(vertices)
outputSize = (100, 32)
targetVertices = np.array([
[0, outputSize[1] - 1],
[0, 0],
[outputSize[0] - 1, 0],
[outputSize[0] - 1, outputSize[1] - 1]], dtype="float32")
rotationMatrix = cv.getPerspectiveTransform(vertices, targetVertices)
result = cv.warpPerspective(frame, rotationMatrix, outputSize)
return result
def decodeText(scores):
text = ""
alphabet = "0123456789abcdefghijklmnopqrstuvwxyz"
for i in range(scores.shape[0]):
c = np.argmax(scores[i][0])
if c != 0:
text += alphabet[c - 1]
else:
text += '-'
# adjacent same letters as well as background text must be removed to get the final output
char_list = []
for i in range(len(text)):
if text[i] != '-' and (not (i > 0 and text[i] == text[i - 1])):
char_list.append(text[i])
return ''.join(char_list)
def decodeBoundingBoxes(scores, geometry, scoreThresh):
detections = []
confidences = []
############ CHECK DIMENSIONS AND SHAPES OF geometry AND scores ############
assert len(scores.shape) == 4, "Incorrect dimensions of scores"
assert len(geometry.shape) == 4, "Incorrect dimensions of geometry"
assert scores.shape[0] == 1, "Invalid dimensions of scores"
assert geometry.shape[0] == 1, "Invalid dimensions of geometry"
assert scores.shape[1] == 1, "Invalid dimensions of scores"
assert geometry.shape[1] == 5, "Invalid dimensions of geometry"
assert scores.shape[2] == geometry.shape[2], "Invalid dimensions of scores and geometry"
assert scores.shape[3] == geometry.shape[3], "Invalid dimensions of scores and geometry"
height = scores.shape[2]
width = scores.shape[3]
for y in range(0, height):
# Extract data from scores
scoresData = scores[0][0][y]
x0_data = geometry[0][0][y]
x1_data = geometry[0][1][y]
x2_data = geometry[0][2][y]
x3_data = geometry[0][3][y]
anglesData = geometry[0][4][y]
for x in range(0, width):
score = scoresData[x]
# If score is lower than threshold score, move to next x
if (score < scoreThresh):
continue
# Calculate offset
offsetX = x * 4.0
offsetY = y * 4.0
angle = anglesData[x]
# Calculate cos and sin of angle
cosA = math.cos(angle)
sinA = math.sin(angle)
h = x0_data[x] + x2_data[x]
w = x1_data[x] + x3_data[x]
# Calculate offset
offset = ([offsetX + cosA * x1_data[x] + sinA * x2_data[x], offsetY - sinA * x1_data[x] + cosA * x2_data[x]])
# Find points for rectangle
p1 = (-sinA * h + offset[0], -cosA * h + offset[1])
p3 = (-cosA * w + offset[0], sinA * w + offset[1])
center = (0.5 * (p1[0] + p3[0]), 0.5 * (p1[1] + p3[1]))
detections.append((center, (w, h), -1 * angle * 180.0 / math.pi))
confidences.append(float(score))
# Return detections and confidences
return [detections, confidences]
def main():
# Read and store arguments
confThreshold = args.thr
nmsThreshold = args.nms
inpWidth = args.width
inpHeight = args.height
modelDetector = args.model
modelRecognition = args.ocr
# Load network
detector = cv.dnn.readNet(modelDetector)
recognizer = cv.dnn.readNet(modelRecognition)
# Create a new named window
kWinName = "EAST: An Efficient and Accurate Scene Text Detector"
cv.namedWindow(kWinName, cv.WINDOW_NORMAL)
outNames = []
outNames.append("feature_fusion/Conv_7/Sigmoid")
outNames.append("feature_fusion/concat_3")
# Open a video file or an image file or a camera stream
cap = cv.VideoCapture(args.input if args.input else 0)
tickmeter = cv.TickMeter()
while cv.waitKey(1) < 0:
# Read frame
hasFrame, frame = cap.read()
if not hasFrame:
cv.waitKey()
break
# Get frame height and width
height_ = frame.shape[0]
width_ = frame.shape[1]
rW = width_ / float(inpWidth)
rH = height_ / float(inpHeight)
# Create a 4D blob from frame.
blob = cv.dnn.blobFromImage(frame, 1.0, (inpWidth, inpHeight), (123.68, 116.78, 103.94), True, False)
# Run the detection model
detector.setInput(blob)
tickmeter.start()
outs = detector.forward(outNames)
tickmeter.stop()
# Get scores and geometry
scores = outs[0]
geometry = outs[1]
[boxes, confidences] = decodeBoundingBoxes(scores, geometry, confThreshold)
# Apply NMS
indices = cv.dnn.NMSBoxesRotated(boxes, confidences, confThreshold, nmsThreshold)
for i in indices:
# get 4 corners of the rotated rect
vertices = cv.boxPoints(boxes[i])
# scale the bounding box coordinates based on the respective ratios
for j in range(4):
vertices[j][0] *= rW
vertices[j][1] *= rH
# get cropped image using perspective transform
if modelRecognition:
cropped = fourPointsTransform(frame, vertices)
cropped = cv.cvtColor(cropped, cv.COLOR_BGR2GRAY)
# Create a 4D blob from cropped image
blob = cv.dnn.blobFromImage(cropped, size=(100, 32), mean=127.5, scalefactor=1 / 127.5)
recognizer.setInput(blob)
# Run the recognition model
tickmeter.start()
result = recognizer.forward()
tickmeter.stop()
# decode the result into text
wordRecognized = decodeText(result)
cv.putText(frame, wordRecognized, (int(vertices[1][0]), int(vertices[1][1])), cv.FONT_HERSHEY_SIMPLEX,
0.5, (255, 0, 0))
for j in range(4):
p1 = (int(vertices[j][0]), int(vertices[j][1]))
p2 = (int(vertices[(j + 1) % 4][0]), int(vertices[(j + 1) % 4][1]))
cv.line(frame, p1, p2, (0, 255, 0), 1)
# Put efficiency information
label = 'Inference time: %.2f ms' % (tickmeter.getTimeMilli())
cv.putText(frame, label, (0, 15), cv.FONT_HERSHEY_SIMPLEX, 0.5, (0, 255, 0))
# Display the frame
cv.imshow(kWinName, frame)
tickmeter.reset()
if __name__ == "__main__":
main()