Single channel uint8 input fails with `low_contrast_enhancement=True`

[rossbar]

MRE:

>>> from cellSAM.cellsam_pipeline import cellsam_pipeline
>>> import imageio.v3 as iio
>>> img = iio.imread("sample_imgs/ep_micro.png")
>>> mask = cellsam_pipeline(img, low_contrast_enhancement=True, use_wsi=True, visualize=False, gauge_cell_size=False)
Traceback (most recent call last)
   ...
ValueError: Images of type float must be between -1 and 1

[emiglietta]

I had the exact same experience. Using the same sample image and with all other parameters set to default.

Here's the full stack trace:

---------------------------------------------------------------------------
ValueError                                Traceback (most recent call last)
Cell In[31], line 10
      6 print(img.sum(axis=(0, 1)))
      8 # mask = cellsam_pipeline(img, use_wsi=False)
---> 10 mask = cellsam_pipeline(img, 
     11                         chunks=256, 
     12                         model_path=None, 
     13                         bbox_threshold=0.4, 
     14                         low_contrast_enhancement=True, 
     15                         swap_channels=False, 
     16                         use_wsi=False, 
     17                         gauge_cell_size=False, 
     18                         block_size=400, 
     19                         overlap=56, 
     20                         iou_depth=56, 
     21                         iou_threshold=0.5)

File ~/anaconda3/envs/cellsam_napari/lib/python3.13/site-packages/cellSAM/cellsam_pipeline.py:190, in cellsam_pipeline(img, chunks, model_path, bbox_threshold, low_contrast_enhancement, swap_channels, use_wsi, gauge_cell_size, block_size, overlap, iou_depth, iou_threshold)
    187 img = normalize_image(img) 
    189 if low_contrast_enhancement:
--> 190     img = enhance_low_contrast(img)
    192 inp = da.from_array(img, chunks=chunks)
    194 if use_wsi:
...
    315 computation_type = _dtype_itemsize(
    316     itemsize_out, dtype_in, np.float32, np.float64
    317 )

ValueError: Images of type float must be between -1 and 1.