app_utils.py

# From http://www.pyimagesearch.com/2015/12/21/increasing-webcam-fps-with-python-and-opencv/

import struct
import six
import collections
import cv2
import datetime
from threading import Thread
from matplotlib import colors


# class FPS:
#     def __init__(self):
#         # store the start time, end time, and total number of frames
#         # that were examined between the start and end intervals
#         self._start = None
#         self._end = None
#         self._numFrames = 0
#
#     def start(self):
#         # start the timer
#         self._start = datetime.datetime.now()
#         return self
#
#     def stop(self):
#         # stop the timer
#         self._end = datetime.datetime.now()
#
#     def update(self):
#         # increment the total number of frames examined during the
#         # start and end intervals
#         self._numFrames += 1
#
#     def elapsed(self):
#         # return the total number of seconds between the start and
#         # end interval
#         return (self._end - self._start).total_seconds()
#
#     def fps(self):
#         # compute the (approximate) frames per second
#         return self._numFrames / self.elapsed()


class WebcamVideoStream:
    def __init__(self, src, width, height):
        # initialize the video camera stream and read the first frame
        # from the stream
        self.stream = cv2.VideoCapture(src)
        self.stream.set(cv2.CAP_PROP_FRAME_WIDTH, width)
        self.stream.set(cv2.CAP_PROP_FRAME_HEIGHT, height)
        #(self.grabbed, self.frame) = self.stream.read()

        # initialize the variable used to indicate if the thread should
        # be stopped
        self.stopped = False

    def start(self):
        # start the thread to read frames from the video stream
        Thread(target=self.update, args=()).start()
        return self

    def update(self):
        # keep looping infinitely until the thread is stopped
        while True:
            # if the thread indicator variable is set, stop the thread
            if self.stopped:
                return

            # otherwise, read the next frame from the stream
            (self.grabbed, self.frame) = self.stream.read()

    def read(self):
        # return the frame most recently read
        (self.grabbed, self.frame) = self.stream.read()
        return self.frame

    def stop(self):
        # indicate that the thread should be stopped
        self.stopped = True


def standard_colors():
    colors = [
        'AliceBlue', 'Chartreuse', 'Aqua', 'Aquamarine', 'Azure', 'Beige', 'Bisque',
        'BlanchedAlmond', 'BlueViolet', 'BurlyWood', 'CadetBlue', 'AntiqueWhite',
        'Chocolate', 'Coral', 'CornflowerBlue', 'Cornsilk', 'Crimson', 'Cyan',
        'DarkCyan', 'DarkGoldenRod', 'DarkGrey', 'DarkKhaki', 'DarkOrange',
        'DarkOrchid', 'DarkSalmon', 'DarkSeaGreen', 'DarkTurquoise', 'DarkViolet',
        'DeepPink', 'DeepSkyBlue', 'DodgerBlue', 'FireBrick', 'FloralWhite',
        'ForestGreen', 'Fuchsia', 'Gainsboro', 'GhostWhite', 'Gold', 'GoldenRod',
        'Salmon', 'Tan', 'HoneyDew', 'HotPink', 'IndianRed', 'Ivory', 'Khaki',
        'Lavender', 'LavenderBlush', 'LawnGreen', 'LemonChiffon', 'LightBlue',
        'LightCoral', 'LightCyan', 'LightGoldenRodYellow', 'LightGray', 'LightGrey',
        'LightGreen', 'LightPink', 'LightSalmon', 'LightSeaGreen', 'LightSkyBlue',
        'LightSlateGray', 'LightSlateGrey', 'LightSteelBlue', 'LightYellow', 'Lime',
        'LimeGreen', 'Linen', 'Magenta', 'MediumAquaMarine', 'MediumOrchid',
        'MediumPurple', 'MediumSeaGreen', 'MediumSlateBlue', 'MediumSpringGreen',
        'MediumTurquoise', 'MediumVioletRed', 'MintCream', 'MistyRose', 'Moccasin',
        'NavajoWhite', 'OldLace', 'Olive', 'OliveDrab', 'Orange', 'OrangeRed',
        'Orchid', 'PaleGoldenRod', 'PaleGreen', 'PaleTurquoise', 'PaleVioletRed',
        'PapayaWhip', 'PeachPuff', 'Peru', 'Pink', 'Plum', 'PowderBlue', 'Purple',
        'Red', 'RosyBrown', 'RoyalBlue', 'SaddleBrown', 'Green', 'SandyBrown',
        'SeaGreen', 'SeaShell', 'Sienna', 'Silver', 'SkyBlue', 'SlateBlue',
        'SlateGray', 'SlateGrey', 'Snow', 'SpringGreen', 'SteelBlue', 'GreenYellow',
        'Teal', 'Thistle', 'Tomato', 'Turquoise', 'Violet', 'Wheat', 'White',
        'WhiteSmoke', 'Yellow', 'YellowGreen'
    ]
    return colors


def color_name_to_rgb():
    colors_rgb = []
    for key, value in colors.cnames.items():
        colors_rgb.append((key, struct.unpack('BBB', bytes.fromhex(value.replace('#', '')))))
    return dict(colors_rgb)


def draw_boxes_and_labels(
        boxes,
        classes,
        scores,
        category_index,
        instance_masks=None,
        keypoints=None,
        max_boxes_to_draw=20,
        min_score_thresh=.5,
        agnostic_mode=False):
    """Returns boxes coordinates, class names and colors

    Args:
      boxes: a numpy array of shape [N, 4]
      classes: a numpy array of shape [N]
      scores: a numpy array of shape [N] or None.  If scores=None, then
        this function assumes that the boxes to be plotted are groundtruth
        boxes and plot all boxes as black with no classes or scores.
      category_index: a dict containing category dictionaries (each holding
        category index `id` and category name `name`) keyed by category indices.
      instance_masks: a numpy array of shape [N, image_height, image_width], can
        be None
      keypoints: a numpy array of shape [N, num_keypoints, 2], can
        be None
      max_boxes_to_draw: maximum number of boxes to visualize.  If None, draw
        all boxes.
      min_score_thresh: minimum score threshold for a box to be visualized
      agnostic_mode: boolean (default: False) controlling whether to evaluate in
        class-agnostic mode or not.  This mode will display scores but ignore
        classes.
    """
    # Create a display string (and color) for every box location, group any boxes
    # that correspond to the same location.
    box_to_display_str_map = collections.defaultdict(list)
    box_to_color_map = collections.defaultdict(str)
    box_to_instance_masks_map = {}
    box_to_keypoints_map = collections.defaultdict(list)
    if not max_boxes_to_draw:
        max_boxes_to_draw = boxes.shape[0]
    for i in range(min(max_boxes_to_draw, boxes.shape[0])):
        if scores is None or scores[i] > min_score_thresh:
            box = tuple(boxes[i].tolist())
            if instance_masks is not None:
                box_to_instance_masks_map[box] = instance_masks[i]
            if keypoints is not None:
                box_to_keypoints_map[box].extend(keypoints[i])
            if scores is None:
                box_to_color_map[box] = 'black'
            else:
                if not agnostic_mode:
                    if classes[i] in category_index.keys():
                        class_name = category_index[classes[i]]['name']
                    else:
                        class_name = 'N/A'
                    display_str = '{}: {}%'.format(
                        class_name,
                        int(100 * scores[i]))
                else:
                    display_str = 'score: {}%'.format(int(100 * scores[i]))
                box_to_display_str_map[box].append(display_str)
                if agnostic_mode:
                    box_to_color_map[box] = 'DarkOrange'
                else:
                    box_to_color_map[box] = standard_colors()[
                        classes[i] % len(standard_colors())]

    # Store all the coordinates of the boxes, class names and colors
    color_rgb = color_name_to_rgb()
    rect_points = []
    class_names = []
    class_colors = []
    for box, color in six.iteritems(box_to_color_map):
        ymin, xmin, ymax, xmax = box
        rect_points.append(dict(ymin=ymin, xmin=xmin, ymax=ymax, xmax=xmax))
        class_names.append(box_to_display_str_map[box])
        class_colors.append(color_rgb[color.lower()])
    return rect_points, class_names, class_colors