CNN learning stagnation - machine-learning

Question

I have created a simulation of the CNN I am trying to use on video data set.
I set the test data to all one single image on all frames for positive examples and 0 for negative examples. I thought this would learn very quickly. But it does not move at all.
Using current versions of Keras & Tensorflow on Windows 10 64bit.
First question, is my logic wrong? Should I expect the learning of this test data to quickly reach high accuracy?
Is there something wrong with my model or parameters? I have been trying a number of changes but still get the same problem.
Is the sample size (56) too small?
# testing feature extraction model.
import time
import numpy as np, cv2
import sys
import os
import keras
import tensorflow as tf
from keras.models import Sequential
from keras.layers import Dense, Dropout, Activation, Flatten, BatchNormalization
from keras.layers import Conv3D, MaxPooling3D
from keras.optimizers import SGD,rmsprop, adam
from keras import regularizers
from keras.initializers import Constant
from keras.models import Model
#set gpu options
gpu_options = tf.GPUOptions(per_process_gpu_memory_fraction=.99, allocator_type = 'BFC')
sess = tf.Session(config=tf.ConfigProto(log_device_placement=True, gpu_options=gpu_options))
config = tf.ConfigProto()
batch_size = 5
num_classes = 1
epochs = 50
nvideos = 56
nframes = 55
nchan = 3
nrows = 480
ncols = 640
#load any single image, resize if needed
img = cv2.imread('C:\\Users\\david\\Documents\\AutonomousSS\\single frame.jpg',cv2.IMREAD_COLOR)
img = cv2.resize(img,(640,480))
x_learn = np.random.randint(0,255,(nvideos,nframes,nrows,ncols,nchan),dtype=np.uint8)
y_learn = np.array([[1],[1],[1],[0],[1],[0],[1],[0],[1],[0],
[1],[0],[0],[1],[0],[0],[1],[0],[1],[0],
[1],[0],[1],[1],[0],[1],[0],[0],[1],[1],
[1],[0],[1],[0],[1],[0],[1],[0],[1],[0],
[0],[1],[0],[0],[1],[0],[1],[0],[1],[0],
[1],[1],[0],[1],[0],[0]],np.uint8)
#each sample, each frame is either the single image for postive examples or 0 for negative examples.
for i in range (nvideos):
if y_learn[i] == 0 :
x_learn[i]=0
else:
x_learn[i,:nframes]=img
#build model
m_loss = 'mean_squared_error'
m_opt = SGD(lr=0.001, decay=1e-6, momentum=0.9, nesterov=True)
m_met = 'acc'
model = Sequential()
# 1st layer group
model.add(Conv3D(32, (3, 3,3), activation='relu',padding="same", name="conv1a", strides=(3, 3, 3),
kernel_initializer = 'glorot_normal',
trainable=False,
input_shape=(nframes,nrows,ncols,nchan)))
#model.add(BatchNormalization(axis=1))
model.add(Conv3D(32, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv1b", activation="relu"))
#model.add(BatchNormalization(axis=1))
model.add(MaxPooling3D(padding="valid", trainable=False, pool_size=(1, 5, 5), name="pool1", strides=(2, 2, 2)))
# 2nd layer group
model.add(Conv3D(128, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv2a", activation="relu"))
model.add(Conv3D(128, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv2b", activation="relu"))
#model.add(BatchNormalization(axis=1))
model.add(MaxPooling3D(padding="valid", trainable=False, pool_size=(1, 5, 5), name="pool2", strides=(2, 2, 2)))
# 3rd layer group
model.add(Conv3D(256, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv3a", activation="relu"))
model.add(Conv3D(256, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv3b", activation="relu"))
#model.add(BatchNormalization(axis=1))
model.add(MaxPooling3D(padding="valid", trainable=False, pool_size=(1, 5, 5), name="pool3", strides=(2, 2, 2)))
# 4th layer group
model.add(Conv3D(512, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv4a", activation="relu"))
model.add(Conv3D(512, (3, 3, 3), trainable=False, strides=(1, 1, 1), padding="same", name="conv4b", activation="relu"))
#model.add(BatchNormalization(axis=1))
model.add(MaxPooling3D(padding="valid", trainable=False, pool_size=(1, 5, 5), name="pool4", strides=(2, 2, 2)))
model.add(Flatten(name='flatten',trainable=False))
model.add(Dense(512,activation='relu', trainable=True,name='den0'))
model.add(Dense(num_classes,activation='softmax',name='den1'))
print (model.summary())
#compile model
model.compile(loss=m_loss,
optimizer=m_opt,
metrics=[m_met])
print ('compiled')
#set callbacks
from keras import backend as K
K.set_learning_phase(0) #set learning phase
tb = keras.callbacks.TensorBoard(log_dir=sample_root_path+'logs', histogram_freq=0,
write_graph=True, write_images=False)
tb.set_model(model)
reduce_lr = keras.callbacks.ReduceLROnPlateau(monitor='loss', factor=0.2,verbose=1,
patience=2, min_lr=0.000001)
reduce_lr.set_model(model)
ear_stop = keras.callbacks.EarlyStopping(monitor='loss', min_delta=0, patience=4, verbose=1, mode='auto')
ear_stop.set_model(model)
#fit
history = model.fit(x_learn, y_learn,
batch_size=batch_size,
callbacks=[reduce_lr,tb, ear_stop],
verbose=1,
validation_split=0.1,
shuffle = True,
epochs=epochs)
score = model.evaluate(x_learn, y_learn, batch_size=batch_size)
print(str(model.metrics_names) + ": " + str(score))
As usual, thanks for any and all help.
added output...
_________________________________________________________________
Layer (type) Output Shape Param #
=================================================================
conv1a (Conv3D) (None, 19, 160, 214, 32) 2624
_________________________________________________________________
conv1b (Conv3D) (None, 19, 160, 214, 32) 27680
_________________________________________________________________
pool1 (MaxPooling3D) (None, 10, 78, 105, 32) 0
_________________________________________________________________
conv2a (Conv3D) (None, 10, 78, 105, 128) 110720
_________________________________________________________________
conv2b (Conv3D) (None, 10, 78, 105, 128) 442496
_________________________________________________________________
pool2 (MaxPooling3D) (None, 5, 37, 51, 128) 0
_________________________________________________________________
conv3a (Conv3D) (None, 5, 37, 51, 256) 884992
_________________________________________________________________
conv3b (Conv3D) (None, 5, 37, 51, 256) 1769728
_________________________________________________________________
pool3 (MaxPooling3D) (None, 3, 17, 24, 256) 0
_________________________________________________________________
conv4a (Conv3D) (None, 3, 17, 24, 512) 3539456
_________________________________________________________________
conv4b (Conv3D) (None, 3, 17, 24, 512) 7078400
_________________________________________________________________
pool4 (MaxPooling3D) (None, 2, 7, 10, 512) 0
_________________________________________________________________
flatten (Flatten) (None, 71680) 0
_________________________________________________________________
den0 (Dense) (None, 512) 36700672
_________________________________________________________________
den1 (Dense) (None, 1) 513
=================================================================
Total params: 50,557,281
Trainable params: 36,701,185
Non-trainable params: 13,856,096
_________________________________________________________________
None
compiled
Train on 50 samples, validate on 6 samples
Epoch 1/50
50/50 [==============================] - 20s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 2/50
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 3/50
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 4/50
45/50 [==========================>...] - ETA: 1s - loss: 0.5111 - acc: 0.4889
Epoch 00003: reducing learning rate to 0.00020000000949949026.
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 5/50
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 6/50
45/50 [==========================>...] - ETA: 1s - loss: 0.5111 - acc: 0.4889
Epoch 00005: reducing learning rate to 4.0000001899898055e-05.
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 7/50
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 8/50
45/50 [==========================>...] - ETA: 1s - loss: 0.4889 - acc: 0.5111
Epoch 00007: reducing learning rate to 8.000000525498762e-06.
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 9/50
50/50 [==============================] - 16s - loss: 0.5000 - acc: 0.5000 - val_loss: 0.5000 - val_acc: 0.5000
Epoch 00008: early stopping
56/56 [==============================] - 12s
['loss', 'acc']: [0.50000001516725334, 0.5000000127724239]

Answer 1

Your layers are set to trainable=False(apart from the last dense layer). Therefore your CNN cannot learn. In addition you won´t be able to train just on a single sample.
If you run into performance issues on your GPU switch to CPU or AWS or reduce your image size.