Grad_cam / app.py
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import tensorflow as tf
import numpy as np
from tensorflow import keras
from keras.layers import Input, Lambda, Dense, Flatten, Rescaling
from keras.models import Model
import PIL
#function for creating model
#returns model, its inputs, Xception's last conv output, the whole model's outputs
def create_model_mod():
inputs = keras.Input(shape = (160,160,3))
#normalizing pixel values
r = Rescaling(scale = 1./255)(inputs)
x = base_model(r, training = False)
gap = keras.layers.GlobalAveragePooling2D()(x)
outputs = keras.layers.Dense(1,activation = 'linear')(gap)
model = keras.Model(inputs, outputs)
model.compile(
loss = keras.losses.BinaryCrossentropy(from_logits = True),
optimizer = keras.optimizers.Adam(0.001),
metrics = ["accuracy"]
)
return model, inputs, x, outputs
def create_heatmap(model, imgs):
#predicting the images and getting the conv outputs and predictions
with tf.GradientTape() as tape:
maps, preds = model(imgs);
#computing gradients of predictions w.r.t the feature maps
grads = tape.gradient(preds, maps)
# global average pooling of each feature map
gap_grads = tf.reduce_mean(grads, axis=(0, 1, 2))
#multiplying each pooled value with its correponding feature map
# maps = maps[0]
heatmap = maps @ gap_grads[..., tf.newaxis]
#removing the extra dimension of value 1
heatmap = tf.squeeze(heatmap)
#applying relu activation
heatmap = tf.keras.activations.relu(heatmap)
return heatmap, preds.numpy()
def superimpose_single(heatmap, img, alpha = 0.4):
heatmap = np.uint8(255 * heatmap)
# Use jet colormap to colorize heatmap
jet = cm.get_cmap("jet")
# Use RGB values of the colormap
jet_colors = jet(np.arange(256))[:, :3]
jet_heatmap = jet_colors[heatmap]
# Create an image with RGB colorized heatmap
jet_heatmap = keras.utils.array_to_img(jet_heatmap)
jet_heatmap = jet_heatmap.resize((160,160))
jet_heatmap = keras.utils.img_to_array(jet_heatmap)
# Superimpose the heatmap on original image
superimposed_img = jet_heatmap * alpha + img
# superimposed_img = keras.utils.array_to_img(superimposed_img)
return superimposed_img
def gen_grad_img_single(weights, img, alpha = 0.4):
model_mod, input, x, output = create_model_mod()
model_mod.load_weights(weights)
grad_model = Model(input, [x, output])
heatmaps, y_pred = create_heatmap(grad_model, img)
for i in range(len(y_pred)):
if y_pred[i] > 0.5: y_pred[i] = 1
else: y_pred[i] = 0
img = superimpose_single(heatmaps, img[0])
return np.array(img).astype('uint8'), y_pred
weights = "weights.h5"
# img, y_pred = gen_grad_img_single(weights, img)
demo = gr.Interface(
fn = gen_grad_img_single,
inputs = gr.Image(type = "pil", shape = (224,224)),
# outputs = [gr.outputs.Label(num_top_classes = 2, label = 'Classifiaction'), gr.Textbox('infer_time', label = 'Inference Time(ms)')]
outputs = ["image", gr.Textbox('y_pred', label = 'Prediction')]
)
demo.launch()