Optimizing the access and changing of value of SLIC superpixels

Question

I'm trying to do semantic segmentation using a SLIC variant and want to create a mask for the original image where each segment is colored (according to its class) based on available point-based annotations. If there is no point-based annotation in that segment, then leave is as 0.

I currently have x, y points and their associated labels for an image and a (slow) method that finds and colors the desired segments. I'm familiar with vectorization or the 'pythonic' was of doing things, but I can't seem to speed up this last for-loop and would love some advice or references on optimization. Thanks.

# Point-based annotations
annotation = pd.read_csv("a_dataframe.csv") # [X, Y, Label]
color_label = {'class 1' : 25, 'class 2' : 50, 'class 3' : 75}

# Uses CPU to create single segmented image with current params
slic = SlicAvx2(num_components = n_segments, compactness = n_compactness)
segmented_image = slic.iterate(cv2.cvtColor(each_image, cv2.COLOR_RGB2LAB)) 

# Finds the segments of interest and records their ID
X = np.array(each_annotation.iloc[:, 0], dtype = 'uint8')
Y = np.array(each_annotation.iloc[:, 1], dtype = 'uint8')
L = np.array(each_annotation.iloc[:, 2], dtype = 'str')  # Labels
DS = segmented_image[X, Y]                               # Desired Segments

# Empty mask, marks the segments of interest with the classes of the point in them
mask = np.zeros(each_image.shape[:2], dtype = "uint8")

# Would ideally like to find a more quickly way of doing this
for (index, segVal) in enumerate(DS):
   mask[segmented_image == segVal] = color_label.get(L[index])

I have essentially what I would like to replace that loop with here:

[mask[segmented_image == s] for i, s in enumerate(DS)]

but I'm not able to assign X, Y locations with the appropriate Label in mask. I thought it would be something similar to this:

[mask[segmented_image == s] for i, s in enumerate(DS)] = color_label.get(L[i])

but it appears that I'm trying to assign a color value to the lists I'm generating...

Answer 1

Are you looking for ind2rgb?
A way to convert an indexed map (one index per slic segment, possible same index for multiple regions) and convert it to RGB image based on a map from index to color.