import colorsys from typing import Union import numpy as np import cv2 import matplotlib.colors as mplc import pycocotools.mask as mask_util import matplotlib.figure as mplfigure from matplotlib.backends.backend_agg import FigureCanvasAgg import matplotlib as mpl from enum import Enum, unique from PIL import Image _LARGE_MASK_AREA_THRESH = 120000 _COLORS = ( np.array( [ 0.000, 0.447, 0.741, 0.850, 0.325, 0.098, 0.929, 0.694, 0.125, 0.494, 0.184, 0.556, 0.466, 0.674, 0.188, 0.301, 0.745, 0.933, 0.635, 0.078, 0.184, 0.300, 0.300, 0.300, 0.600, 0.600, 0.600, 1.000, 0.000, 0.000, 1.000, 0.500, 0.000, 0.749, 0.749, 0.000, 0.000, 1.000, 0.000, 0.000, 0.000, 1.000, 0.667, 0.000, 1.000, 0.333, 0.333, 0.000, 0.333, 0.667, 0.000, 0.333, 1.000, 0.000, 0.667, 0.333, 0.000, 0.667, 0.667, 0.000, 0.667, 1.000, 0.000, 1.000, 0.333, 0.000, 1.000, 0.667, 0.000, 1.000, 1.000, 0.000, 0.000, 0.333, 0.500, 0.000, 0.667, 0.500, 0.000, 1.000, 0.500, 0.333, 0.000, 0.500, 0.333, 0.333, 0.500, 0.333, 0.667, 0.500, 0.333, 1.000, 0.500, 0.667, 0.000, 0.500, 0.667, 0.333, 0.500, 0.667, 0.667, 0.500, 0.667, 1.000, 0.500, 1.000, 0.000, 0.500, 1.000, 0.333, 0.500, 1.000, 0.667, 0.500, 1.000, 1.000, 0.500, 0.000, 0.333, 1.000, 0.000, 0.667, 1.000, 0.000, 1.000, 1.000, 0.333, 0.000, 1.000, 0.333, 0.333, 1.000, 0.333, 0.667, 1.000, 0.333, 1.000, 1.000, 0.667, 0.000, 1.000, 0.667, 0.333, 1.000, 0.667, 0.667, 1.000, 0.667, 1.000, 1.000, 1.000, 0.000, 1.000, 1.000, 0.333, 1.000, 1.000, 0.667, 1.000, 0.333, 0.000, 0.000, 0.500, 0.000, 0.000, 0.667, 0.000, 0.000, 0.833, 0.000, 0.000, 1.000, 0.000, 0.000, 0.000, 0.167, 0.000, 0.000, 0.333, 0.000, 0.000, 0.500, 0.000, 0.000, 0.667, 0.000, 0.000, 0.833, 0.000, 0.000, 1.000, 0.000, 0.000, 0.000, 0.167, 0.000, 0.000, 0.333, 0.000, 0.000, 0.500, 0.000, 0.000, 0.667, 0.000, 0.000, 0.833, 0.000, 0.000, 1.000, 0.000, 0.000, 0.000, 0.143, 0.143, 0.143, 0.857, 0.857, 0.857, 1.000, 1.000, 1.000, ] ) .astype(np.float32) .reshape(-1, 3) ) def random_color(rgb=False, maximum=255): """ Args: rgb (bool): whether to return RGB colors or BGR colors. maximum (int): either 255 or 1 Returns: ndarray: a vector of 3 numbers """ idx = np.random.randint(0, len(_COLORS)) ret = _COLORS[idx] * maximum if not rgb: ret = ret[::-1] return ret @unique class ColorMode(Enum): """ Enum of different color modes to use for instance visualizations. """ IMAGE = 0 """ Picks a random color for every instance and overlay segmentations with low opacity. """ SEGMENTATION = 1 """ Let instances of the same category have similar colors (from metadata.thing_colors), and overlay them with high opacity. This provides more attention on the quality of segmentation. """ IMAGE_BW = 2 """ Same as IMAGE, but convert all areas without masks to gray-scale. Only available for drawing per-instance mask predictions. """ class VisImage: def __init__(self, img, scale=1.0): """ Args: img (ndarray): an RGB image of shape (H, W, 3) in range [0, 255]. scale (float): scale the input image """ self.img = img self.scale = scale self.width, self.height = img.shape[1], img.shape[0] self._setup_figure(img) def _setup_figure(self, img): """ Args: Same as in :meth:`__init__()`. Returns: fig (matplotlib.pyplot.figure): top level container for all the image plot elements. ax (matplotlib.pyplot.Axes): contains figure elements and sets the coordinate system. """ fig = mplfigure.Figure(frameon=False) self.dpi = fig.get_dpi() # add a small 1e-2 to avoid precision lost due to matplotlib's truncation # (https://github.com/matplotlib/matplotlib/issues/15363) fig.set_size_inches( (self.width * self.scale + 1e-2) / self.dpi, (self.height * self.scale + 1e-2) / self.dpi, ) self.canvas = FigureCanvasAgg(fig) # self.canvas = mpl.backends.backend_cairo.FigureCanvasCairo(fig) ax = fig.add_axes([0.0, 0.0, 1.0, 1.0]) ax.axis("off") self.fig = fig self.ax = ax self.reset_image(img) def reset_image(self, img): """ Args: img: same as in __init__ """ img = img.astype("uint8") self.ax.imshow( img, extent=(0, self.width, self.height, 0), interpolation="nearest" ) def save(self, filepath): """ Args: filepath (str): a string that contains the absolute path, including the file name, where the visualized image will be saved. """ self.fig.savefig(filepath) def get_image(self): """ Returns: ndarray: the visualized image of shape (H, W, 3) (RGB) in uint8 type. The shape is scaled w.r.t the input image using the given `scale` argument. """ canvas = self.canvas s, (width, height) = canvas.print_to_buffer() # buf = io.BytesIO() # works for cairo backend # canvas.print_rgba(buf) # width, height = self.width, self.height # s = buf.getvalue() buffer = np.frombuffer(s, dtype="uint8") img_rgba = buffer.reshape(height, width, 4) rgb, alpha = np.split(img_rgba, [3], axis=2) return rgb.astype("uint8") class GenericMask: """ Attribute: polygons (list[ndarray]): list[ndarray]: polygons for this mask. Each ndarray has format [x, y, x, y, ...] mask (ndarray): a binary mask """ def __init__(self, mask_or_polygons, height, width): self._mask = self._polygons = self._has_holes = None self.height = height self.width = width m = mask_or_polygons if isinstance(m, dict): # RLEs assert "counts" in m and "size" in m if isinstance(m["counts"], list): # uncompressed RLEs h, w = m["size"] assert h == height and w == width m = mask_util.frPyObjects(m, h, w) self._mask = mask_util.decode(m)[:, :] return if isinstance(m, list): # list[ndarray] self._polygons = [np.asarray(x).reshape(-1) for x in m] return if isinstance(m, np.ndarray): # assumed to be a binary mask assert m.shape[1] != 2, m.shape assert m.shape == ( height, width, ), f"mask shape: {m.shape}, target dims: {height}, {width}" self._mask = m.astype("uint8") return raise ValueError( "GenericMask cannot handle object {} of type '{}'".format(m, type(m)) ) @property def mask(self): if self._mask is None: self._mask = self.polygons_to_mask(self._polygons) return self._mask @property def polygons(self): if self._polygons is None: self._polygons, self._has_holes = self.mask_to_polygons(self._mask) return self._polygons @property def has_holes(self): if self._has_holes is None: if self._mask is not None: self._polygons, self._has_holes = self.mask_to_polygons(self._mask) else: self._has_holes = ( False # if original format is polygon, does not have holes ) return self._has_holes def mask_to_polygons(self, mask): # cv2.RETR_CCOMP flag retrieves all the contours and arranges them to a 2-level # hierarchy. External contours (boundary) of the object are placed in hierarchy-1. # Internal contours (holes) are placed in hierarchy-2. # cv2.CHAIN_APPROX_NONE flag gets vertices of polygons from contours. mask = np.ascontiguousarray( mask ) # some versions of cv2 does not support incontiguous arr res = cv2.findContours( mask.astype("uint8"), cv2.RETR_CCOMP, cv2.CHAIN_APPROX_NONE ) hierarchy = res[-1] if hierarchy is None: # empty mask return [], False has_holes = (hierarchy.reshape(-1, 4)[:, 3] >= 0).sum() > 0 res = res[-2] res = [x.flatten() for x in res] # These coordinates from OpenCV are integers in range [0, W-1 or H-1]. # We add 0.5 to turn them into real-value coordinate space. A better solution # would be to first +0.5 and then dilate the returned polygon by 0.5. res = [x + 0.5 for x in res if len(x) >= 6] return res, has_holes def polygons_to_mask(self, polygons): rle = mask_util.frPyObjects(polygons, self.height, self.width) rle = mask_util.merge(rle) return mask_util.decode(rle)[:, :] def area(self): return self.mask.sum() def bbox(self): p = mask_util.frPyObjects(self.polygons, self.height, self.width) p = mask_util.merge(p) bbox = mask_util.toBbox(p) bbox[2] += bbox[0] bbox[3] += bbox[1] return bbox class Visualizer: """ Visualizer that draws data about detection/segmentation on images. It contains methods like `draw_{text,box,circle,line,binary_mask,polygon}` that draw primitive objects to images, as well as high-level wrappers like `draw_{instance_predictions,sem_seg,panoptic_seg_predictions,dataset_dict}` that draw composite data in some pre-defined style. Note that the exact visualization style for the high-level wrappers are subject to change. Style such as color, opacity, label contents, visibility of labels, or even the visibility of objects themselves (e.g. when the object is too small) may change according to different heuristics, as long as the results still look visually reasonable. To obtain a consistent style, you can implement custom drawing functions with the abovementioned primitive methods instead. If you need more customized visualization styles, you can process the data yourself following their format documented in tutorials (:doc:`/tutorials/models`, :doc:`/tutorials/datasets`). This class does not intend to satisfy everyone's preference on drawing styles. This visualizer focuses on high rendering quality rather than performance. It is not designed to be used for real-time applications. """ # TODO implement a fast, rasterized version using OpenCV def __init__( self, img_rgb: Union[Image.Image, np.ndarray], scale=1.0, instance_mode=ColorMode.IMAGE, ): """ Args: img_rgb: a numpy array of shape (H, W, C), where H and W correspond to the height and width of the image respectively. C is the number of color channels. The image is required to be in RGB format since that is a requirement of the Matplotlib library. The image is also expected to be in the range [0, 255]. instance_mode (ColorMode): defines one of the pre-defined style for drawing instances on an image. """ if type(img_rgb) == np.ndarray: img_rgb = img_rgb[:, :, ::-1] else: img_rgb = np.array(img_rgb)[:, :, ::-1] self.img = np.asarray(img_rgb).clip(0, 255).astype(np.uint8) self.output = VisImage(self.img, scale=scale) # too small texts are useless, therefore clamp to 9 self._default_font_size = max( np.sqrt(self.output.height * self.output.width) // 90, 10 // scale ) self._instance_mode = instance_mode def draw_binary_mask( self, binary_mask, color=None, *, edge_color=None, text=None, alpha=0.5, area_threshold=10, ): """ Args: binary_mask (ndarray): numpy array of shape (H, W), where H is the image height and W is the image width. Each value in the array is either a 0 or 1 value of uint8 type. color: color of the mask. Refer to `matplotlib.colors` for a full list of formats that are accepted. If None, will pick a random color. edge_color: color of the polygon edges. Refer to `matplotlib.colors` for a full list of formats that are accepted. text (str): if None, will be drawn on the object alpha (float): blending efficient. Smaller values lead to more transparent masks. area_threshold (float): a connected component smaller than this area will not be shown. Returns: output (VisImage): image object with mask drawn. """ if color is None: color = random_color(rgb=True, maximum=1) color = mplc.to_rgb(color) has_valid_segment = False binary_mask = binary_mask.astype("uint8") # opencv needs uint8 mask = GenericMask(binary_mask, self.output.height, self.output.width) shape2d = (binary_mask.shape[0], binary_mask.shape[1]) if not mask.has_holes: # draw polygons for regular masks for segment in mask.polygons: area = mask_util.area( mask_util.frPyObjects([segment], shape2d[0], shape2d[1]) ) if area < (area_threshold or 0): continue has_valid_segment = True segment = segment.reshape(-1, 2) self.draw_polygon( segment, color=color, edge_color=edge_color, alpha=alpha ) else: # TODO: Use Path/PathPatch to draw vector graphics: # https://stackoverflow.com/questions/8919719/how-to-plot-a-complex-polygon rgba = np.zeros(shape2d + (4,), dtype="float32") rgba[:, :, :3] = color rgba[:, :, 3] = (mask.mask == 1).astype("float32") * alpha has_valid_segment = True self.output.ax.imshow( rgba, extent=(0, self.output.width, self.output.height, 0) ) if text is not None and has_valid_segment: lighter_color = self._change_color_brightness(color, brightness_factor=0.7) self._draw_text_in_mask(binary_mask, text, lighter_color) return self.output def draw_polygon(self, segment, color, edge_color=None, alpha=0.5): """ Args: segment: numpy array of shape Nx2, containing all the points in the polygon. color: color of the polygon. Refer to `matplotlib.colors` for a full list of formats that are accepted. edge_color: color of the polygon edges. Refer to `matplotlib.colors` for a full list of formats that are accepted. If not provided, a darker shade of the polygon color will be used instead. alpha (float): blending efficient. Smaller values lead to more transparent masks. Returns: output (VisImage): image object with polygon drawn. """ if edge_color is None: # make edge color darker than the polygon color if alpha > 0.8: edge_color = self._change_color_brightness( color, brightness_factor=-0.7 ) else: edge_color = color edge_color = mplc.to_rgb(edge_color) + (1,) polygon = mpl.patches.Polygon( segment, fill=True, facecolor=mplc.to_rgb(color) + (alpha,), edgecolor=edge_color, linewidth=max(self._default_font_size // 15 * self.output.scale, 1), ) self.output.ax.add_patch(polygon) return self.output """ Internal methods: """ def _change_color_brightness(self, color, brightness_factor): """ Depending on the brightness_factor, gives a lighter or darker color i.e. a color with less or more saturation than the original color. Args: color: color of the polygon. Refer to `matplotlib.colors` for a full list of formats that are accepted. brightness_factor (float): a value in [-1.0, 1.0] range. A lightness factor of 0 will correspond to no change, a factor in [-1.0, 0) range will result in a darker color and a factor in (0, 1.0] range will result in a lighter color. Returns: modified_color (tuple[double]): a tuple containing the RGB values of the modified color. Each value in the tuple is in the [0.0, 1.0] range. """ assert brightness_factor >= -1.0 and brightness_factor <= 1.0 color = mplc.to_rgb(color) polygon_color = colorsys.rgb_to_hls(*mplc.to_rgb(color)) modified_lightness = polygon_color[1] + (brightness_factor * polygon_color[1]) modified_lightness = 0.0 if modified_lightness < 0.0 else modified_lightness modified_lightness = 1.0 if modified_lightness > 1.0 else modified_lightness modified_color = colorsys.hls_to_rgb( polygon_color[0], modified_lightness, polygon_color[2] ) return modified_color def _draw_text_in_mask(self, binary_mask, text, color): """ Find proper places to draw text given a binary mask. """ # TODO sometimes drawn on wrong objects. the heuristics here can improve. _num_cc, cc_labels, stats, centroids = cv2.connectedComponentsWithStats( binary_mask, 8 ) if stats[1:, -1].size == 0: return largest_component_id = np.argmax(stats[1:, -1]) + 1 # draw text on the largest component, as well as other very large components. for cid in range(1, _num_cc): if cid == largest_component_id or stats[cid, -1] > _LARGE_MASK_AREA_THRESH: # median is more stable than centroid # center = centroids[largest_component_id] center = np.median((cc_labels == cid).nonzero(), axis=1)[::-1] self.draw_text(text, center, color=color) def get_output(self): """ Returns: output (VisImage): the image output containing the visualizations added to the image. """ return self.output def apply_threshold(pred: np.ndarray) -> np.ndarray: """Apply threshold to a salient map Args: pred (np.ndarray): each pixel is in range [0, 255] Returns: np.ndarray: each pixel is only 0.0 or 1.0 """ binary_mask = pred / 255.0 binary_mask[binary_mask >= 0.5] = 1.0 binary_mask[binary_mask < 0.5] = 0.0 return binary_mask def normalize(data: np.ndarray) -> np.ndarray: return (data - data.min()) / (data.max() - data.min() + 1e-8) def post_processing_depth(depth: np.ndarray) -> np.ndarray: depth = (normalize(depth) * 255).astype(np.uint8) return cv2.applyColorMap(depth, cv2.COLORMAP_OCEAN) def apply_vis_to_image( rgb: np.ndarray, binary_mask: np.ndarray, color: np.ndarray ) -> np.ndarray: if rgb.shape[:2] != binary_mask.shape[:2]: print(rgb.shape, binary_mask.shape) binary_mask = cv2.resize(binary_mask, [rgb.shape[1], rgb.shape[0]]) visualizer = Visualizer(rgb) vis_image: VisImage = visualizer.draw_binary_mask(binary_mask, color) vis_image = vis_image.get_image()[:, :, ::-1] return vis_image