From c862fd7ee763e5c90cf21bc56c3be6ec84ea856e Mon Sep 17 00:00:00 2001
From: algol <dkazanc@hotmail.com>
Date: Fri, 10 Jul 2026 13:42:14 +0100
Subject: [PATCH] adding the capability of changing the bit depth

---
 httomolib/misc/blend.py        |  2 +-
 httomolib/misc/images.py       | 26 ++++++++++++++++++++++++
 tests/test_misc/test_images.py | 36 ++++++++++++++++++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)

diff --git a/httomolib/misc/blend.py b/httomolib/misc/blend.py
index c3ff44f..911351a 100644
--- a/httomolib/misc/blend.py
+++ b/httomolib/misc/blend.py
@@ -56,7 +56,7 @@ def seam_blend_stitched_data(
     path_to_stiched_params_file : Optional, str
             Path to the text file with the stiching parameters. If provided 'seam_index' and 'blending_width' parameters will be overridden by the ones provided in the file.
     shift_seam_index : int
-        performs a shift of the seam index with seam_index - shift_seam_index. This is purely an HTTomo related feature and should be ignored by users. 
+        performs a shift of the seam index with seam_index - shift_seam_index. This is purely an HTTomo related feature and should be ignored by users.
     Raises
     ----------
         ValueError: When data is not 3D.
diff --git a/httomolib/misc/images.py b/httomolib/misc/images.py
index e3a658d..4705561 100644
--- a/httomolib/misc/images.py
+++ b/httomolib/misc/images.py
@@ -57,6 +57,7 @@ def save_to_images(
     offset: int = 0,
     watermark_vals: Optional[tuple] = None,
     asynchronous: bool = False,
+    bit_depth: int = 32,
 ):
     """
     Saves data as 2D tif, png or jpeg images. The images will be saved using the same data type as the input data,
@@ -88,6 +89,8 @@ def save_to_images(
         be of the same size as len(data[axis]).
     asynchronous: bool
         Perform write operations synchronously or asynchronously.
+    bit_depth: int
+        The function will rescale the data into 8 or 16 bit, assuming that the input is 32 bit
     """
 
     ### Data and parameters checks ###
@@ -115,7 +118,11 @@ def save_to_images(
         methods_name,
     )
     __check_variable_type(asynchronous, [bool], "asynchronous", [], methods_name)
+    __check_variable_type(bit_depth, [int], "bit_depth", [8, 16, 32], methods_name)
     ###################################
+    if bit_depth != 32:
+        data = _float32_to_uint16_8(data, bit_depth)
+
     bits_data_type = data.dtype.itemsize * 8
 
     if file_format != "tif" and bits_data_type in [16, 32, 64]:
@@ -323,3 +330,22 @@ async def _waiting_loop(queue) -> None:
 
 def __find_decimals(value):
     return abs(decimal.Decimal(str(value)).as_tuple().exponent)
+
+
+def _float32_to_uint16_8(data, bit_depth):
+    data = np.asarray(data, dtype=np.float32)
+
+    dmin = data.min()
+    dmax = data.max()
+
+    if dmax == dmin:
+        if bit_depth == 8:
+            return np.zeros(data.shape, dtype=np.uint8)
+        else:
+            return np.zeros(data.shape, dtype=np.uint16)
+
+    scaled = (data - dmin) / (dmax - dmin)
+    if bit_depth == 8:
+        return (scaled * 255).round().astype(np.uint8)
+    else:
+        return (scaled * 65535).round().astype(np.uint16)
diff --git a/tests/test_misc/test_images.py b/tests/test_misc/test_images.py
index 9c4e14c..06faf28 100644
--- a/tests/test_misc/test_images.py
+++ b/tests/test_misc/test_images.py
@@ -128,6 +128,42 @@ def test_save_to_images_tiff_float32(
     assert len(files) == 128
 
 
+def test_save_to_images_uint16_from_float32(
+    host_data: np.ndarray, host_flats: np.ndarray, tmp_path: pathlib.Path
+):
+    host_data_norm = np.float32(host_data / np.mean(host_flats, axis=0))
+
+    save_to_images(
+        host_data_norm,
+        tmp_path / "save_to_images",
+        file_format="tif",
+        bit_depth=16,
+    )
+
+    folder = tmp_path / "save_to_images" / f"images{'16'}bit_tif"
+    assert folder.exists()
+    files = list(folder.glob("*"))
+    assert len(files) == 128
+
+
+def test_save_to_images_uint8_from_float32(
+    host_data: np.ndarray, host_flats: np.ndarray, tmp_path: pathlib.Path
+):
+    host_data_norm = np.float32(host_data / np.mean(host_flats, axis=0))
+
+    save_to_images(
+        host_data_norm,
+        tmp_path / "save_to_images",
+        file_format="tif",
+        bit_depth=8,
+    )
+
+    folder = tmp_path / "save_to_images" / f"images{'8'}bit_tif"
+    assert folder.exists()
+    files = list(folder.glob("*"))
+    assert len(files) == 128
+
+
 def test_save_to_images_watermark_2D(host_data: np.ndarray, tmp_path: pathlib.Path):
     DTYPE = np.uint8
     bits = np.dtype(DTYPE).itemsize * 8