knn and decision tree

This commit is contained in:
pranavbrkr 2023-11-22 13:49:21 -07:00
parent 4492dc6677
commit 6c8663ed46
3 changed files with 4417 additions and 9844 deletions

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@ -1311,7 +1311,7 @@
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.10.5"
"version": "3.11.4"
}
},
"nbformat": 4,

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@ -37,86 +37,12 @@ from pymongo import MongoClient
import matplotlib.pyplot as plt
class GridPartition:
"""Class transform to partition image into (rows, cols) grid"""
def __init__(self, rows, cols):
self.rows = rows
self.cols = cols
def __call__(self, img):
# img is in (C,(H,W)) format, so first element is channel
img_width, img_height = img.size()[1:]
cell_width = img_width // self.cols
cell_height = img_height // self.rows
grids = []
for i in range(self.rows):
for j in range(self.cols):
left = j * cell_width
right = left + cell_width
top = i * cell_height
bottom = top + cell_height
# Slice out
grid = img[:, left:right, top:bottom]
grids.append(grid)
return grids
def compute_gradient_histogram(grid_cell):
"""Compute HOG using [-1,0,1] masks for gradient"""
histograms = []
# Convert grid cell to NumPy array
grid_array = np.array(grid_cell, dtype=np.float32)
grid_array = grid_array.reshape(
grid_array.shape[1], grid_array.shape[2]
) # ignore extra dimension
# Compute the gradient using first-order central differences
dx = cv2.Sobel(
grid_array, cv2.CV_32F, dx=1, dy=0, ksize=1
) # first order x derivative = [-1, 0, 1]
dy = cv2.Sobel(
grid_array, cv2.CV_32F, dx=0, dy=1, ksize=1
) # first order y derivative = [-1, 0, 1]^T
# Compute magnitude and direction of gradients
magnitude = np.sqrt(dx**2 + dy**2)
direction = np.arctan2(dy, dx) * 180 / np.pi # in degrees
# Compute HOG - 9 bins, counted across the range of -180 to 180 degrees, weighted by gradient magnitude
histogram, _ = np.histogram(direction, bins=9, range=(-180, 180), weights=magnitude)
histograms.append(histogram)
return histograms
def compute_histograms_for_grid(grid):
histograms = [compute_gradient_histogram(grid_cell) for grid_cell in grid]
return np.array(histograms).flatten()
def combine_histograms(grid_histograms):
return torch.Tensor(grid_histograms).view(10, 10, 9)
HOG_transform = transforms.Compose(
[
transforms.Grayscale(num_output_channels=1), # grayscale transform
transforms.Resize((100, 300)), # resize to H:W=100:300
GridPartition(
rows=10, cols=10
), # partition into grid of 10 rows, 10 columns as a list
compute_histograms_for_grid,
combine_histograms,
]
)
valid_classification_methods = {
"m-nn": 1,
"decision tree": 2,
"ppr": 3,
}
def getCollection(db, collection):
"""Load feature descriptor collection from MongoDB"""
@ -124,30 +50,6 @@ def getCollection(db, collection):
return client[db][collection]
def datasetTransform(image):
"""Transform while loading dataset as scaled tensors of shape (channels, (img_shape))"""
return transforms.Compose(
[
transforms.ToTensor() # ToTensor by default scales to [0,1] range, the input range for ResNet
]
)(image)
def loadDataset(dataset):
"""Load TorchVision dataset with the defined transform"""
return dataset(
root=getenv("DATASET_PATH"),
download=False, # True if you wish to download for first time
transform=datasetTransform,
)
dataset = loadDataset(Caltech101)
NUM_LABELS = 101
NUM_IMAGES = 4339
def euclidean_distance_measure(img_1_fd, img_2_fd):
img_1_fd_reshaped = img_1_fd.flatten()
img_2_fd_reshaped = img_2_fd.flatten()
@ -156,100 +58,6 @@ def euclidean_distance_measure(img_1_fd, img_2_fd):
return math.dist(img_1_fd_reshaped, img_2_fd_reshaped)
def loadResnet():
"""Load ResNet50 pre-trained model with default weights"""
# Load model
model = resnet50(weights=ResNet50_Weights.DEFAULT)
# try to use Nvidia GPU
if torch.cuda.is_available():
dev = torch.device("cuda")
torch.cuda.empty_cache()
else:
dev = torch.device("cpu")
model = model.to(dev)
model.eval() # switch to inference mode - important! since we're using pre-trained model
return model, dev
model, dev = loadResnet()
class FeatureExtractor(torch.nn.Module):
"""Feature extractor module for all layers at once"""
def __init__(self, model, layers):
super().__init__()
self.model = model
self.layers = layers
self._features = {layer: None for layer in layers} # store layer outputs here
# Create hooks for all specified layers at once
for layer_id in layers:
layer = dict(self.model.named_modules())[
layer_id
] # get actual layer in the model
layer.register_forward_hook(
self.save_outputs_hook(layer_id)
) # register feature extractor hook on layer
# Hook to save output of layer
def save_outputs_hook(self, layer_id):
def fn(_module, _input, output):
self._features[layer_id] = output
return fn
# Forward pass returns extracted features
def forward(self, input):
_ = self.model(input)
return self._features
def resnet_extractor(image):
"""Extract image features from avgpool, layer3 and fc layers of ResNet50"""
resized_image = (
torch.Tensor(np.array(transforms.Resize((224, 224))(image)).flatten())
.view(1, 3, 224, 224)
.to(dev)
)
# Attach all hooks on model and extract features
resnet_features = FeatureExtractor(model=model, layers=["avgpool", "layer3", "fc"])
features = resnet_features(resized_image)
avgpool_2048 = features["avgpool"]
# Reshape the vector into row pairs of elements and average across rows
avgpool_1024_fd = torch.mean(avgpool_2048.view(-1, 2), axis=1)
layer3_1024_14_14 = features["layer3"]
# Reshape the vector into 1024 rows of 196 elements and average across rows
layer3_1024_fd = torch.mean(layer3_1024_14_14.view(1024, -1), axis=1)
fc_1000_fd = features["fc"].view(1000)
return (
avgpool_1024_fd.detach().cpu().tolist(),
layer3_1024_fd.detach().cpu().tolist(),
fc_1000_fd.detach().cpu().tolist(),
)
def resnet_output(image):
"""Get image features from ResNet50 (full execution) and apply a softmax layer"""
resized_image = (
torch.Tensor(np.array(transforms.Resize((224, 224))(image)).flatten())
.view(1, 3, 224, 224)
.to(dev)
)
with torch.no_grad():
features = model(resized_image)
features = torch.nn.Softmax()(features)
return features.detach().cpu().tolist()
valid_feature_models = {
"cm": "cm_fd",
"hog": "hog_fd",
@ -258,28 +66,3 @@ valid_feature_models = {
"fc": "fc_fd",
"resnet": "resnet_fd",
}
def predict_m_nn_classifier(fd_collection, m, feature_model, selected_image_fd):
"""
Create the m-NN classifier from the selected feature space
"""
assert (
feature_model in valid_feature_models.values()
), "feature_moel should be one of " + str(list(valid_feature_models.keys()))
all_images = list(fd_collection.find())
feature_ids = [img["image_id"] for img in all_images]
feature_vectors = np.array(
[np.array(img[feature_model]).flatten() for img in all_images]
)
distances = []
for fd, id in zip(feature_vectors, feature_ids):
distances.append({"image_id": id, "distance": euclidean_distance_measure(selected_image_fd, fd)})
distances = sorted(distances, key=lambda x: x["distance"])
return distances[:10]