Éanna Ó Catháin | 145c88f | 2020-11-16 14:12:11 +0000 | [diff] [blame] | 1 | # Copyright © 2020 Arm Ltd and Contributors. All rights reserved. |
| 2 | # SPDX-License-Identifier: MIT |
| 3 | |
| 4 | """ |
| 5 | This file contains helper functions for reading video/image data and |
| 6 | pre/postprocessing of video/image data using OpenCV. |
| 7 | """ |
| 8 | |
| 9 | import os |
| 10 | |
| 11 | import cv2 |
| 12 | import numpy as np |
| 13 | |
| 14 | import pyarmnn as ann |
| 15 | |
| 16 | |
| 17 | def preprocess(frame: np.ndarray, input_binding_info: tuple): |
| 18 | """ |
| 19 | Takes a frame, resizes, swaps channels and converts data type to match |
| 20 | model input layer. The converted frame is wrapped in a const tensor |
| 21 | and bound to the input tensor. |
| 22 | |
| 23 | Args: |
| 24 | frame: Captured frame from video. |
| 25 | input_binding_info: Contains shape and data type of model input layer. |
| 26 | |
| 27 | Returns: |
| 28 | Input tensor. |
| 29 | """ |
| 30 | # Swap channels and resize frame to model resolution |
| 31 | frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB) |
| 32 | resized_frame = resize_with_aspect_ratio(frame, input_binding_info) |
| 33 | |
| 34 | # Expand dimensions and convert data type to match model input |
Éanna Ó Catháin | 65d5d2d | 2021-08-20 14:41:38 +0100 | [diff] [blame] | 35 | if input_binding_info[1].GetDataType() == ann.DataType_Float32: |
| 36 | data_type = np.float32 |
| 37 | resized_frame = resized_frame.astype("float32")/255 |
| 38 | else: |
| 39 | data_type = np.uint8 |
| 40 | |
Éanna Ó Catháin | 145c88f | 2020-11-16 14:12:11 +0000 | [diff] [blame] | 41 | resized_frame = np.expand_dims(np.asarray(resized_frame, dtype=data_type), axis=0) |
| 42 | assert resized_frame.shape == tuple(input_binding_info[1].GetShape()) |
| 43 | |
| 44 | input_tensors = ann.make_input_tensors([input_binding_info], [resized_frame]) |
| 45 | return input_tensors |
| 46 | |
| 47 | |
Éanna Ó Catháin | 65d5d2d | 2021-08-20 14:41:38 +0100 | [diff] [blame] | 48 | |
Éanna Ó Catháin | 145c88f | 2020-11-16 14:12:11 +0000 | [diff] [blame] | 49 | def resize_with_aspect_ratio(frame: np.ndarray, input_binding_info: tuple): |
| 50 | """ |
| 51 | Resizes frame while maintaining aspect ratio, padding any empty space. |
| 52 | |
| 53 | Args: |
| 54 | frame: Captured frame. |
| 55 | input_binding_info: Contains shape of model input layer. |
| 56 | |
| 57 | Returns: |
| 58 | Frame resized to the size of model input layer. |
| 59 | """ |
| 60 | aspect_ratio = frame.shape[1] / frame.shape[0] |
| 61 | model_height, model_width = list(input_binding_info[1].GetShape())[1:3] |
| 62 | |
| 63 | if aspect_ratio >= 1.0: |
| 64 | new_height, new_width = int(model_width / aspect_ratio), model_width |
| 65 | b_padding, r_padding = model_height - new_height, 0 |
| 66 | else: |
| 67 | new_height, new_width = model_height, int(model_height * aspect_ratio) |
| 68 | b_padding, r_padding = 0, model_width - new_width |
| 69 | |
| 70 | # Resize and pad any empty space |
| 71 | frame = cv2.resize(frame, (new_width, new_height), interpolation=cv2.INTER_LINEAR) |
| 72 | frame = cv2.copyMakeBorder(frame, top=0, bottom=b_padding, left=0, right=r_padding, |
| 73 | borderType=cv2.BORDER_CONSTANT, value=[0, 0, 0]) |
| 74 | return frame |
| 75 | |
| 76 | |
| 77 | def create_video_writer(video: cv2.VideoCapture, video_path: str, output_path: str): |
| 78 | """ |
| 79 | Creates a video writer object to write processed frames to file. |
| 80 | |
| 81 | Args: |
| 82 | video: Video capture object, contains information about data source. |
| 83 | video_path: User-specified video file path. |
| 84 | output_path: Optional path to save the processed video. |
| 85 | |
| 86 | Returns: |
| 87 | Video writer object. |
| 88 | """ |
| 89 | _, ext = os.path.splitext(video_path) |
| 90 | |
| 91 | if output_path is not None: |
| 92 | assert os.path.isdir(output_path) |
| 93 | |
| 94 | i, filename = 0, os.path.join(output_path if output_path is not None else str(), f'object_detection_demo{ext}') |
| 95 | while os.path.exists(filename): |
| 96 | i += 1 |
| 97 | filename = os.path.join(output_path if output_path is not None else str(), f'object_detection_demo({i}){ext}') |
| 98 | |
| 99 | video_writer = cv2.VideoWriter(filename=filename, |
| 100 | fourcc=get_source_encoding_int(video), |
| 101 | fps=int(video.get(cv2.CAP_PROP_FPS)), |
| 102 | frameSize=(int(video.get(cv2.CAP_PROP_FRAME_WIDTH)), |
| 103 | int(video.get(cv2.CAP_PROP_FRAME_HEIGHT)))) |
| 104 | return video_writer |
| 105 | |
| 106 | |
| 107 | def init_video_file_capture(video_path: str, output_path: str): |
| 108 | """ |
| 109 | Creates a video capture object from a video file. |
| 110 | |
| 111 | Args: |
| 112 | video_path: User-specified video file path. |
| 113 | output_path: Optional path to save the processed video. |
| 114 | |
| 115 | Returns: |
| 116 | Video capture object to capture frames, video writer object to write processed |
| 117 | frames to file, plus total frame count of video source to iterate through. |
| 118 | """ |
| 119 | if not os.path.exists(video_path): |
| 120 | raise FileNotFoundError(f'Video file not found for: {video_path}') |
| 121 | video = cv2.VideoCapture(video_path) |
| 122 | if not video.isOpened: |
| 123 | raise RuntimeError(f'Failed to open video capture from file: {video_path}') |
| 124 | |
| 125 | video_writer = create_video_writer(video, video_path, output_path) |
| 126 | iter_frame_count = range(int(video.get(cv2.CAP_PROP_FRAME_COUNT))) |
| 127 | return video, video_writer, iter_frame_count |
| 128 | |
| 129 | |
| 130 | def init_video_stream_capture(video_source: int): |
| 131 | """ |
| 132 | Creates a video capture object from a device. |
| 133 | |
| 134 | Args: |
| 135 | video_source: Device index used to read video stream. |
| 136 | |
| 137 | Returns: |
| 138 | Video capture object used to capture frames from a video stream. |
| 139 | """ |
| 140 | video = cv2.VideoCapture(video_source) |
| 141 | if not video.isOpened: |
| 142 | raise RuntimeError(f'Failed to open video capture for device with index: {video_source}') |
| 143 | print('Processing video stream. Press \'Esc\' key to exit the demo.') |
| 144 | return video |
| 145 | |
| 146 | |
| 147 | def draw_bounding_boxes(frame: np.ndarray, detections: list, resize_factor, labels: dict): |
| 148 | """ |
| 149 | Draws bounding boxes around detected objects and adds a label and confidence score. |
| 150 | |
| 151 | Args: |
| 152 | frame: The original captured frame from video source. |
| 153 | detections: A list of detected objects in the form [class, [box positions], confidence]. |
| 154 | resize_factor: Resizing factor to scale box coordinates to output frame size. |
| 155 | labels: Dictionary of labels and colors keyed on the classification index. |
| 156 | """ |
| 157 | for detection in detections: |
| 158 | class_idx, box, confidence = [d for d in detection] |
| 159 | label, color = labels[class_idx][0].capitalize(), labels[class_idx][1] |
| 160 | |
| 161 | # Obtain frame size and resized bounding box positions |
| 162 | frame_height, frame_width = frame.shape[:2] |
| 163 | x_min, y_min, x_max, y_max = [int(position * resize_factor) for position in box] |
| 164 | |
| 165 | # Ensure box stays within the frame |
| 166 | x_min, y_min = max(0, x_min), max(0, y_min) |
| 167 | x_max, y_max = min(frame_width, x_max), min(frame_height, y_max) |
| 168 | |
| 169 | # Draw bounding box around detected object |
| 170 | cv2.rectangle(frame, (x_min, y_min), (x_max, y_max), color, 2) |
| 171 | |
| 172 | # Create label for detected object class |
| 173 | label = f'{label} {confidence * 100:.1f}%' |
| 174 | label_color = (0, 0, 0) if sum(color)>200 else (255, 255, 255) |
| 175 | |
| 176 | # Make sure label always stays on-screen |
| 177 | x_text, y_text = cv2.getTextSize(label, cv2.FONT_HERSHEY_DUPLEX, 1, 1)[0][:2] |
| 178 | |
| 179 | lbl_box_xy_min = (x_min, y_min if y_min<25 else y_min - y_text) |
| 180 | lbl_box_xy_max = (x_min + int(0.55 * x_text), y_min + y_text if y_min<25 else y_min) |
| 181 | lbl_text_pos = (x_min + 5, y_min + 16 if y_min<25 else y_min - 5) |
| 182 | |
| 183 | # Add label and confidence value |
| 184 | cv2.rectangle(frame, lbl_box_xy_min, lbl_box_xy_max, color, -1) |
| 185 | cv2.putText(frame, label, lbl_text_pos, cv2.FONT_HERSHEY_DUPLEX, 0.50, |
| 186 | label_color, 1, cv2.LINE_AA) |
| 187 | |
| 188 | |
| 189 | def get_source_encoding_int(video_capture): |
| 190 | return int(video_capture.get(cv2.CAP_PROP_FOURCC)) |