401-object-detection-webcam: Live Object Detection with OpenVINO

# Imports
import collections
import os
import sys
import time

import cv2
import numpy as np
from IPython import display
from openvino.runtime import Core

sys.path.append("../utils")
import notebook_utils as utils

# Download the Model
# directory where model will be downloaded
base_model_dir = "model"

# model name as named in Open Model Zoo
model_name = "ssdlite_mobilenet_v2"

download_command = f"omz_downloader " \
                   f"--name {model_name} " \
                   f"--output_dir {base_model_dir} " \
                   f"--cache_dir {base_model_dir}"
! $download_command

# Convert the Model
precision = "FP16"

# output path for the conversion
converted_model_path = f"model/public/{model_name}/{precision}/{model_name}.xml"

if not os.path.exists(converted_model_path):
    convert_command = f"omz_converter " \
                      f"--name {model_name} " \
                      f"--download_dir {base_model_dir} " \
                      f"--precisions {precision}"
    ! $convert_command

# Load the Model
# initialize inference engine
ie_core = Core()
# read the network and corresponding weights from file
model = ie_core.read_model(model=converted_model_path)
# compile the model for the CPU (you can choose manually CPU, GPU, MYRIAD etc.)
# or let the engine choose the best available device (AUTO)
compiled_model = ie_core.compile_model(model=model, device_name="CPU")

# get input and output nodes
input_layer = compiled_model.input(0)
output_layer = compiled_model.output(0)

# get input size
height, width = list(input_layer.shape)[1:3]

# Process Results
# https://tech.amikelive.com/node-718/what-object-categories-labels-are-in-coco-dataset/
classes = [
    "background", "person", "bicycle", "car", "motorcycle", "airplane", "bus", "train",
    "truck", "boat", "traffic light", "fire hydrant", "street sign", "stop sign",
    "parking meter", "bench", "bird", "cat", "dog", "horse", "sheep", "cow", "elephant",
    "bear", "zebra", "giraffe", "hat", "backpack", "umbrella", "shoe", "eye glasses",
    "handbag", "tie", "suitcase", "frisbee", "skis", "snowboard", "sports ball", "kite",
    "baseball bat", "baseball glove", "skateboard", "surfboard", "tennis racket", "bottle",
    "plate", "wine glass", "cup", "fork", "knife", "spoon", "bowl", "banana", "apple",
    "sandwich", "orange", "broccoli", "carrot", "hot dog", "pizza", "donut", "cake", "chair",
    "couch", "potted plant", "bed", "mirror", "dining table", "window", "desk", "toilet",
    "door", "tv", "laptop", "mouse", "remote", "keyboard", "cell phone", "microwave", "oven",
    "toaster", "sink", "refrigerator", "blender", "book", "clock", "vase", "scissors",
    "teddy bear", "hair drier", "toothbrush", "hair brush"
]

# colors for above classes (Rainbow Color Map)
colors = cv2.applyColorMap(
    src=np.arange(0, 255, 255 / len(classes), dtype=np.float32).astype(np.uint8),
    colormap=cv2.COLORMAP_RAINBOW,
).squeeze()


def process_results(frame, results, thresh=0.6):
    # size of the original frame
    h, w = frame.shape[:2]
    # results is a tensor [1, 1, 100, 7]
    results = results.squeeze()
    boxes = []
    labels = []
    scores = []
    for _, label, score, xmin, ymin, xmax, ymax in results:
        # create a box with pixels coordinates from the box with normalized coordinates [0,1]
        boxes.append(
            tuple(map(int, (xmin * w, ymin * h, (xmax - xmin) * w, (ymax - ymin) * h)))
        )
        labels.append(int(label))
        scores.append(float(score))

    # apply non-maximum suppression to get rid of many overlapping entities
    # see https://paperswithcode.com/method/non-maximum-suppression
    # this algorithm returns indices of objects to keep
    indices = cv2.dnn.NMSBoxes(
        bboxes=boxes, scores=scores, score_threshold=thresh, nms_threshold=0.6
    )

    # if there are no boxes
    if len(indices) == 0:
        return []

    # filter detected objects
    return [(labels[idx], scores[idx], boxes[idx]) for idx in indices.flatten()]


def draw_boxes(frame, boxes):
    for label, score, box in boxes:
        # choose color for the label
        color = tuple(map(int, colors[label]))
        # draw box
        x2 = box[0] + box[2]
        y2 = box[1] + box[3]
        cv2.rectangle(img=frame, pt1=box[:2], pt2=(x2, y2), color=color, thickness=3)

        # draw label name inside the box
        cv2.putText(
            img=frame,
            text=f"{classes[label]} {score:.2f}",
            org=(box[0] + 10, box[1] + 30),
            fontFace=cv2.FONT_HERSHEY_COMPLEX,
            fontScale=frame.shape[1] / 1000,
            color=color,
            thickness=1,
            lineType=cv2.LINE_AA,
        )

    return frame

# Main Processing Function
# main processing function to run object detection
def run_object_detection(source=0, flip=False, use_popup=False, skip_first_frames=0):
    player = None
    try:
        # create video player to play with target fps
        player = utils.VideoPlayer(
            source=source, flip=flip, fps=30, skip_first_frames=skip_first_frames
        )
        # start capturing
        player.start()
        if use_popup:
            title = "Press ESC to Exit"
            cv2.namedWindow(
                winname=title, flags=cv2.WINDOW_GUI_NORMAL | cv2.WINDOW_AUTOSIZE
            )

        processing_times = collections.deque()
        while True:
            # grab the frame
            frame = player.next()
            if frame is None:
                print("Source ended")
                break
            # if frame larger than full HD, reduce size to improve the performance
            scale = 1280 / max(frame.shape)
            if scale < 1:
                frame = cv2.resize(
                    src=frame,
                    dsize=None,
                    fx=scale,
                    fy=scale,
                    interpolation=cv2.INTER_AREA,
                )

            # resize image and change dims to fit neural network input
            input_img = cv2.resize(
                src=frame, dsize=(width, height), interpolation=cv2.INTER_AREA
            )
            # create batch of images (size = 1)
            input_img = input_img[np.newaxis, ...]

            # measure processing time

            start_time = time.time()
            # get results
            results = compiled_model([input_img])[output_layer]
            stop_time = time.time()
            # get poses from network results
            boxes = process_results(frame=frame, results=results)

            # draw boxes on a frame
            frame = draw_boxes(frame=frame, boxes=boxes)

            processing_times.append(stop_time - start_time)
            # use processing times from last 200 frames
            if len(processing_times) > 200:
                processing_times.popleft()

            _, f_width = frame.shape[:2]
            # mean processing time [ms]
            processing_time = np.mean(processing_times) * 1000
            fps = 1000 / processing_time
            cv2.putText(
                img=frame,
                text=f"Inference time: {processing_time:.1f}ms ({fps:.1f} FPS)",
                org=(20, 40),
                fontFace=cv2.FONT_HERSHEY_COMPLEX,
                fontScale=f_width / 1000,
                color=(0, 0, 255),
                thickness=1,
                lineType=cv2.LINE_AA,
            )

            # use this workaround if there is flickering
            if use_popup:
                cv2.imshow(winname=title, mat=frame)
                key = cv2.waitKey(1)
                # escape = 27
                if key == 27:
                    break
            else:
                # encode numpy array to jpg
                _, encoded_img = cv2.imencode(
                    ext=".jpg", img=frame, params=[cv2.IMWRITE_JPEG_QUALITY, 100]
                )
                # create IPython image
                i = display.Image(data=encoded_img)
                # display the image in this notebook
                display.clear_output(wait=True)
                display.display(i)
    # ctrl-c
    except KeyboardInterrupt:
        print("Interrupted")
    # any different error
    except RuntimeError as e:
        print(e)
    finally:
        if player is not None:
            # stop capturing
            player.stop()
        if use_popup:
            cv2.destroyAllWindows()

# Run Live Object Detection
run_object_detection(source=0, flip=True, use_popup=False)

# Run Object Detection on a Video File
video_file = "../201-vision-monodepth/data/Coco Walking in Berkeley.mp4"

run_object_detection(source=video_file, flip=False, use_popup=False)