def normalize_pixels(pixels, mean, std):
result = [0.0] * len(pixels)
for i in range(len(pixels)):
result[i] = (pixels[i] - mean) / std
return result
def apply_gamma(pixels, gamma):
result = [0.0] * len(pixels)
for i in range(len(pixels)):
result[i] = pixels[i] ** gamma
return result
def channel_mean(pixels, channels, channel_idx):
total = 0.0
count = 0
for i in range(channel_idx, len(pixels), channels):
total += pixels[i]
count += 1
return total / count if count > 0 else 0.0
if __name__ == "__main__":
import time
pixels = [float(i % 256) / 255.0 for i in range(224 * 224 * 3)]
start = time.time()
for _ in range(50):
normalize_pixels(pixels, 0.485, 0.229)
elapsed = time.time() - start
print(f"normalize_pixels 224x224x3: {elapsed:.3f}s for 50 iterations")
start = time.time()
for _ in range(50):
apply_gamma(pixels, 2.2)
elapsed = time.time() - start
print(f"apply_gamma 224x224x3: {elapsed:.3f}s for 50 iterations")