# Imports
import cv2
import matplotlib.pyplot as plt
import numpy as np
from openvino.runtime import Core
# Load the Model
ie = Core()
model = ie.read_model(model="model/horizontal-text-detection-0001.xml")
compiled_model = ie.compile_model(model=model, device_name="CPU")
input_layer_ir = compiled_model.input(0)
output_layer_ir = compiled_model.output("boxes")
# Load an Image
# Text detection models expects image in BGR format
image = cv2.imread("data/intel_rnb.jpg")
# N,C,H,W = batch size, number of channels, height, width
N, C, H, W = input_layer_ir.shape
# Resize image to meet network expected input sizes
resized_image = cv2.resize(image, (W, H))
# Reshape to network input shape
input_image = np.expand_dims(resized_image.transpose(2, 0, 1), 0)
plt.imshow(cv2.cvtColor(image, cv2.COLOR_BGR2RGB));
# Do Inference
# Create inference request
boxes = compiled_model([input_image])[output_layer_ir]
# Remove zero only boxes
boxes = boxes[~np.all(boxes == 0, axis=1)]
# Visualize Results
# For each detection, the description has the format: [x_min, y_min, x_max, y_max, conf]
# Image passed here is in BGR format with changed width and height. To display it in colors expected by matplotlib we use cvtColor function
def convert_result_to_image(bgr_image, resized_image, boxes, threshold=0.3, conf_labels=True):
# Define colors for boxes and descriptions
colors = {"red": (255, 0, 0), "green": (0, 255, 0)}
# Fetch image shapes to calculate ratio
(real_y, real_x), (resized_y, resized_x) = bgr_image.shape[:2], resized_image.shape[:2]
ratio_x, ratio_y = real_x / resized_x, real_y / resized_y
# Convert base image from bgr to rgb format
rgb_image = cv2.cvtColor(bgr_image, cv2.COLOR_BGR2RGB)
# Iterate through non-zero boxes
for box in boxes:
# Pick confidence factor from last place in array
conf = box[-1]
if conf > threshold:
# Convert float to int and multiply corner position of each box by x and y ratio
# In case that bounding box is found at the top of the image,
# we position upper box bar little lower to make it visible on image
(x_min, y_min, x_max, y_max) = [
int(max(corner_position * ratio_y, 10)) if idx % 2
else int(corner_position * ratio_x)
for idx, corner_position in enumerate(box[:-1])
]
# Draw box based on position, parameters in rectangle function are: image, start_point, end_point, color, thickness
rgb_image = cv2.rectangle(rgb_image, (x_min, y_min), (x_max, y_max), colors["green"], 3)
# Add text to image based on position and confidence
# Parameters in text function are: image, text, bottom-left_corner_textfield, font, font_scale, color, thickness, line_type
if conf_labels:
rgb_image = cv2.putText(
rgb_image,
f"{conf:.2f}",
(x_min, y_min - 10),
cv2.FONT_HERSHEY_SIMPLEX,
0.8,
colors["red"],
1,
cv2.LINE_AA,
)
return rgb_image
plt.figure(figsize=(10, 6))
plt.axis("off")
plt.imshow(convert_result_to_image(image, resized_image, boxes, conf_labels=False));