---
tags:
- Mask
- MaskEnhancement
- MaskRegion
---

# Label Mask Regions (RGB)
## Documentation
- Class name: `SaltMaskRegionLabeling`
- Category: `SALT/Masking/Filter`
- Output node: `False`

This node is designed to label distinct regions within a mask, converting them into visually distinct areas based on connectivity, and outputting these labeled regions as a tensor. It utilizes thresholding and connected component analysis to segment and label different regions, enhancing the interpretability of mask regions by assigning unique colors to each.
## Input types
### Required
- **`masks`**
    - The input masks to be labeled, where each mask is processed to identify and label connected regions based on the specified threshold(s).
    - Comfy dtype: `MASK`
    - Python dtype: `List[torch.Tensor]`
### Optional
- **`threshold`**
    - A list of threshold values to apply binary thresholding on the masks, which is crucial for separating the regions to be labeled. If a single value is provided, it is applied to all masks.
    - Comfy dtype: `INT`
    - Python dtype: `List[int]`
## Output types
- **`images`**
    - Comfy dtype: `IMAGE`
    - The output tensor containing the labeled regions, where each region is assigned a unique color to distinguish it from others. This correction addresses the feedback by correctly identifying the output as a tensor of labeled images, not just 'regions_tensor'.
    - Python dtype: `torch.Tensor`
## Usage tips
- Infra type: `GPU`
- Common nodes: unknown


## Source code
```python
class SaltMaskRegionLabeling:
    @classmethod
    def INPUT_TYPES(cls):
        return {
            "required": {
                "masks": ("MASK",),
            },
            "optional": {
                "threshold": ("INT", {"default": 128, "min": 0, "max": 255, "step": 1}),
            }
        }

    CATEGORY = f"{NAME}/Masking/Filter"

    RETURN_TYPES = ("IMAGE",)
    RETURN_NAMES = ("images",)

    FUNCTION = "region_labeling"

    def region_labeling(self, masks, threshold=[128]):

        if not isinstance(threshold, list):
            threshold = [threshold]

        regions = []
        for i, mask in enumerate(masks):
            pil_image = ImageOps.invert(mask2pil(mask.unsqueeze(0)))
            image_array = np.array(pil_image.convert('L'))

            _, thresh_image = cv2.threshold(image_array, threshold[i if i < len(threshold) else -1], 255, cv2.THRESH_BINARY)

            num_labels, labels_im = cv2.connectedComponents(thresh_image)
            max_label = max(num_labels - 1, 1)

            hues = np.linspace(0, 179, num=max_label + 1, endpoint=False, dtype=np.uint8)

            label_hue = np.zeros_like(labels_im, dtype=np.uint8)
            for i in range(1, num_labels):
                label_hue[labels_im == i] = hues[i]

            saturation = np.uint8(np.where(labels_im == 0, 0, 255))
            value = np.uint8(np.where(labels_im == 0, 0, 255))

            labeled_img = cv2.merge([label_hue, saturation, value])
            labeled_img = cv2.cvtColor(labeled_img, cv2.COLOR_HSV2BGR)

            labeled_pil = Image.fromarray(labeled_img)
            region_tensor = pil2tensor(labeled_pil)
            regions.append(region_tensor)

        regions_tensor = torch.cat(regions, dim=0)
        return (regions_tensor,)

```