utils/vis.py

import matplotlib.pyplot as plt
import numpy as np
import cv2
import math
import itertools
from sklearn.metrics import confusion_matrix, balanced_accuracy_score, precision_score, recall_score
from matplotlib import cm
from mpl_toolkits.mplot3d import Axes3D
from matplotlib.ticker import LinearLocator

def plot_batch(ds, fn, max_samples=9, figscale:int=2):
    """ Plot batch samples from a dataset and save to fn """
    if hasattr(ds,'element_spec'): # ad-hoc test to assess if ds is tf.dataset or not...
        # draw a batch from tf.data dataset
        images, labels = next(iter(ds))
        images = images.numpy()
        labels = labels.numpy()
    else:
        # draw a batch from ImageDataGenerator-based dataset
        images, labels = ds.next()
        # images, labels = ds.take(1)
    
    # limit the number of shown images
    n_samples = min(len(images), max_samples)
    assert n_samples > 0
    root_n = int(math.ceil(math.sqrt(n_samples)))

    f, axs = plt.subplots(root_n, root_n, figsize=(root_n*figscale, root_n*figscale))
    if root_n > 1:
        axs = axs.flat
    
    # find denormalization parameters
    min_image_val = min([np.array(img).min() for img in images])
    max_image_val = max([np.array(img).max() for img in images])

    for i in range(n_samples):
        img = _denorm(images[i], min_image_val, max_image_val)
        ax = axs[i] if root_n > 1 else axs
        ax.imshow(img)
        ax.set_title(labels[i])
        ax.set_axis_off()
    
    # hide rest of the axes
    for j in range(i, root_n*root_n):
        axs[j].set_axis_off()

    plt.savefig(fn, transparent=False)
    plt.close()

def plot_batch_preds(
    images,
    labels,
    preds, 
    fn,
    gradcams=None, 
    title="", 
    max_samples=9, 
    figscale:int=2
    ):
    """ 
    Plot batch samples with preds and labels 
    
    Arguments:
        images     (list): images from dataset batch
        labels     (list): labels from dataset batch
        preds      (list): predictions for items
        fn          (str): filepath to save figure to
        gradcams   (grid): gradcam grid (optional)
        title       (str): plot title
        max_samples (int): max number of samples to plot
        figscale    (int): figure scaling factor. 2=regular, 3=large, 4=larger, etc.
    """
    # limit the number of shown images
    n_samples = min(len(images), max_samples)
    assert n_samples > 0
    root_n = int(math.ceil(math.sqrt(n_samples)))

    # leave some space vertically for the labels
    fig, axs = plt.subplots(root_n, root_n, figsize=(root_n*figscale, (1 + root_n)*figscale))
    if root_n > 1:
        axs = axs.flat

    fig.suptitle(title,fontsize=20)
    
    # find denormalization parameters
    min_image_val = min([np.array(img).min() for img in images])
    max_image_val = max([np.array(img).max() for img in images])
    
    # unpack concatenated gradcam grid
    if gradcams is None:
        gradcam_list = [None for _ in range(n_samples)]
    else:
        gradcam_list = []
        rolling_x = 0; rolling_y = 0
        H,W = images[0].shape[:2]
        orig_h, orig_w = gradcams.shape[:2]
        while rolling_y < orig_h:
            while rolling_x < orig_w:
                gradcam_list.append(gradcams[rolling_y:rolling_y+H, rolling_x:rolling_x+W])
                rolling_x += W
            rolling_x = 0
            rolling_y += H

    for i in range(n_samples):
        img = _denorm(images[i], min_image_val, max_image_val)
        ax = axs[i] if root_n > 1 else axs
        
        # plot a single channel of the image
        ax.imshow(img[:,:,0], cmap='gray')

        # overlay gradcam activations
        if gradcam_list[i] is not None:
            H,W = img.shape[:2]
            ax.imshow(gradcam_list[i], alpha=0.5, extent=(0,H,W,0), interpolation='bilinear')
        
        ax.set_title(f'GT:{labels[i]}\nPred:{preds[i]}')
        ax.set_axis_off()
    
    # hide rest of the axes
    for j in range(i, root_n*root_n):
        axs[j].set_axis_off()

    plt.savefig(fn, transparent=False)
    plt.close()

def _denorm(img, min_image_val, max_image_val):
    """ Denormalize image by a min and max value """
    if min_image_val < 0:
        if max_image_val > 1: # [-127,127]
            img = (img + 127) / 255.
        else: # [-1,1]
            img = (img + 1.) / 2.
    elif max_image_val > 1: # no scaling
        img /= 255.
    else: # [0,1]
        pass
    return np.clip(img, 0,1) 


def plot_history(history, fn, figscale=5):
    metric_keys = history.history.keys()
    # metric keys contain val_ prefixes for validation set, we want to plot these in the same graph with train
    train_keys = [key for key in metric_keys if 'val_' not in key]
    fig, axs = plt.subplots(len(train_keys), 1, figsize=(figscale, figscale*len(train_keys)))

    for i, train_key in enumerate(train_keys):
        val_key = 'val_' + train_key
        assert val_key in metric_keys

        train_metric = history.history[train_key]
        val_metric = history.history[val_key]

        ax = axs[i] if len(train_keys) > 1 else axs

        ax.plot(train_metric, label=f'Training {train_key}')
        ax.plot(val_metric, label=f'Validation {train_key}')
        ax.legend()
        ax.set_ylabel(f'{train_key}')
        ax.set_title(f'Training and Validation {train_key}')

    plt.savefig(fn, transparent=False)
    plt.close()

def plot_confusion_matrix(trues, 
                          preds,
                          target_names,
                          title='Confusion matrix',
                          cmap=None,
                          normalize=True,
                          figsize=(10, 10)):
    """
    given a sklearn confusion matrix (cm), make a nice plot

    Arguments
    ---------
    trues:           Ground truth array

    preds:           Predicted array

    target_names: given classification classes such as [0, 1, 2]
                  the class names, for example: ['high', 'medium', 'low']

    title:        the text to display at the top of the matrix

    cmap:         the gradient of the values displayed from matplotlib.pyplot.cm
                  see http://matplotlib.org/examples/color/colormaps_reference.html
                  plt.get_cmap('jet') or plt.cm.Blues

    normalize:    If False, plot the raw numbers
                  If True, plot the proportions

    figsize:      tuple of matplotlib figure size

    """
    cm = confusion_matrix(trues, preds)

    accuracy = np.trace(cm) / np.sum(cm).astype('float')
    balanced_acc = balanced_accuracy_score(trues, preds)
    misclass = 1 - accuracy

    # calculate precision and recall for each class
    class_scores = '\n\n'
    for i, cl in enumerate(target_names):
        cl_trues = np.where(np.array(trues) == i, 1, 0)
        cl_preds = np.where(np.array(preds) == i, 1, 0)
        precision = precision_score(cl_trues, cl_preds)
        recall = recall_score(cl_trues, cl_preds)
        class_scores += cl + ' precision {:.3f}, recall {:.3f}'.format(precision, recall) + '\n'

    if cmap is None:
        cmap = plt.get_cmap('Blues')

    plt.figure(figsize=figsize)
    plt.imshow(cm, interpolation='nearest', cmap=cmap)
    plt.title(title + class_scores)
    plt.colorbar()

    if target_names is not None:
        tick_marks = np.arange(len(target_names))
        plt.xticks(tick_marks, target_names, rotation=45)
        plt.yticks(tick_marks, target_names)

    if normalize:
        cm = cm.astype('float') / cm.sum(axis=1)[:, np.newaxis]

    thresh = cm.max() / 1.5 if normalize else cm.max() / 2
    for i, j in itertools.product(range(cm.shape[0]), range(cm.shape[1])):
        if normalize:
            plt.text(j, i, "{:0.4f}".format(cm[i, j]),
                     horizontalalignment="center",
                     color="white" if cm[i, j] > thresh else "black")
        else:
            plt.text(j, i, "{:,}".format(cm[i, j]),
                     horizontalalignment="center",
                     color="white" if cm[i, j] > thresh else "black")


    plt.tight_layout()
    plt.ylabel('True label')
    plt.xlabel('Predicted label\naccuracy={:0.4f}; misclass={:0.4f}; balanced accuracy={:0.4f}'.format(accuracy, misclass, balanced_acc))

def plot_surface_v1(heat_map):
    # create the x and y coordinate arrays (here we just use pixel indices)
    heat_gray = cv2.cvtColor(heat_map, cv2.COLOR_BGR2GRAY)
    lena = heat_gray
    xx, yy = np.mgrid[0:lena.shape[0], 0:lena.shape[1]]

    # create the figure
    fig = plt.figure()
    ax = fig.gca(projection='3d')
    # ax2 = fig.add_subplot(1,2,2,projection='3d')
    surf = ax.plot_surface(xx, yy, lena ,rstride=1, cstride=1, cmap=plt.cm.jet,
                    linewidth=0)
    # ax.invert_zaxis()
    # ax.view_init(20,60)
    ax.view_init(30,60)
    fig.colorbar(surf, shrink=0.5, aspect=5)

    # show it
    plt.show()


def plot_surface(fig,heat_map,cnt):
    # create the x and y coordinate arrays (here we just use pixel indices)
    heat_gray = cv2.cvtColor(heat_map, cv2.COLOR_BGR2GRAY)
    lena = heat_gray
    # lena[:60,100:] = heat_gray[:60,:80]
    xx, yy = np.mgrid[0:lena.shape[0], 0:lena.shape[1]]

    # create the figure
    # fig = plt.figure()
    # ax = fig.gca(projection='3d')
    ax = fig.add_subplot(6,5,cnt,projection='3d')
    surf = ax.plot_surface(xx, yy, lena ,rstride=1, cstride=1, cmap=plt.cm.jet,
                    linewidth=0)
    # ax.invert_zaxis()
    ax.view_init(30,60)
    fig.colorbar(surf, shrink=0.5, aspect=5)

def visualize(anchor, positive, negative):
    """Visualize a few triplets from the supplied batches."""

    def show(ax, image):
        ax.imshow(image)
        ax.get_xaxis().set_visible(False)
        ax.get_yaxis().set_visible(False)

    fig = plt.figure(figsize=(9, 9))

    axs = fig.subplots(3, 3)
    for i in range(3):
        show(axs[i, 0], anchor[i])
        show(axs[i, 1], positive[i])
        show(axs[i, 2], negative[i])

def draw_cv2_bbox(img,bboxes,CLASSES,scores=None):
    LABELS = ["Background","Bed","Chair","Wheelchair"]
    COLORS = [(0,0,0),(255, 0, 0),(255, 128, 0),(0,255,00)]
    font = cv2.FONT_HERSHEY_SIMPLEX
    fontScale = 0.5
    thickness = 1
    # CLASSES = CLASSES
    # boxes = request_response['boxes']
    # masks = np.asarray(request_response['masks'])
    # print(bboxes)
    for i, box in enumerate(bboxes):
        class_id = CLASSES[i]
        class_text = LABELS[class_id]
        # pts = results['detection_boxes'][0][i3]
        xmin = int(round(box[0]))
        ymin = int(round(box[1]))
        xmax = int(round(box[2]))
        ymax = int(round(box[3]))
        # print(xmin,ymin,xmax,ymax)
        color = COLORS[class_id]
        img = cv2.rectangle(img,(xmin,ymin),(xmax,ymax),color,1)
        if not scores:
            score = scores[i]
            tmp_txt = f'{score:.3f}'
            img = cv2.putText(img,tmp_txt, (xmin,ymin+5), font, fontScale, color, thickness, cv2.LINE_AA, False)


def draw_bbox(img,bbox, color=(255,0,00)):
        # pts = results['detection_boxes'][0][i3]
        xmin = bbox[0]
        ymin = bbox[1]
        xmax = bbox[2]
        ymax = bbox[3]
        img = cv2.rectangle(img,(xmin,ymin),(xmax,ymax),color,1)
        return img

def consctruct_bbox(xc,yc,width=40,height=30):
    # tmp_ar = 30
    xmin = xc - width+10
    xmax = xc + width+10
    ymin = yc - height
    ymax = yc + height
    return [xmin,ymin,xmax,ymax]

# def draw_bbox(img,bbox, color=(255,0,00)):
#         # pts = results['detection_boxes'][0][i3]
#         xmin = bbox[0]
#         ymin = bbox[1]
#         xmax = bbox[2]
#         ymax = bbox[3]
#         img = cv2.rectangle(img,(xmin,ymin),(xmax,ymax),color,1)
#         return img