c.py

def grad_cam(input_model, model_x, orig_x, category_index, layer_name, class_names):
    output = input_model.output

    final_layer = Lambda(lambda x: target_category_loss(x, category_index, len(class_names)))
    output = final_layer(output)
    model = Model(inputs=input_model.input, outputs=output)
    loss = K.sum(model.layers[-1].output)
    conv_output = model.get_layer(layer_name).output
    grads = normalize(K.gradients(loss, conv_output)[0])
    gradient_function = K.function([model.layers[0].input, K.learning_phase()], [conv_output, grads])

    output, grads_val = gradient_function([model_x, 0])
    output, grads_val = output[0, :], grads_val[0, :, :, :]

    weights = np.mean(grads_val, axis=(0, 1))
    cam = np.zeros(output.shape[0: 2], dtype=np.float32)

    for i, w in enumerate(weights):
        cam += w * output[:, :, i]

    cam = np.maximum(cam, np.zeros(output.shape[0: 2], dtype=np.float32))
    cam = cam.squeeze()
    cam = cv2.applyColorMap(np.uint8(255 * cam / np.max(cam)), cv2.COLORMAP_JET)
    cam = cv2.resize(cam, (np.shape(orig_x)[0], np.shape(orig_x)[1]))
    cam = 0.4 * cam + 0.6 * orig_x
    return np.uint8(cam)