diff --git a/conftest.py b/conftest.py
new file mode 100644
index 0000000..e69de29
diff --git a/pipeline_b/star_detector.py b/pipeline_b/star_detector.py
index e69de29..0887deb 100644
--- a/pipeline_b/star_detector.py
+++ b/pipeline_b/star_detector.py
@@ -0,0 +1,29 @@
+import numpy as np # Je le laisse pour plus tard
+import cv2
+import os
+
+def reading_picture(path):
+    if not os.path.exists(path):
+        raise FileNotFoundError(f"{path} n'existe pas.")
+    pic = cv2.imread(path, cv2.IMREAD_GRAYSCALE)
+    if pic is None:
+        raise ValueError(f"{path} est corrompu ou n'est pas une image valide.")
+    return pic
+
+def blob_detector(picture):
+    params = cv2.SimpleBlobDetector_Params()
+    params.minThreshold = 10
+    params.maxThreshold = 200
+    params.filterByArea = True
+    params.minArea = 4
+    params.filterByCircularity = True
+    params.minCircularity = 0.1
+    params.filterByConvexity = True
+    params.minConvexity = 0.87
+    params.filterByInertia = True
+    params.minInertiaRatio = 0.01
+    # TODO: valeurs provisoires, à recalibrer avec de vraies images de test cette semaine.
+    detector = cv2.SimpleBlobDetector.create(params)
+    stars = detector.detect(picture)
+    result = [star.pt for star in stars]
+    return result
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diff --git a/requirements.txt b/requirements.txt
index 5a99242..f1105af 100644
Binary files a/requirements.txt and b/requirements.txt differ
diff --git a/tests/tests_pipeline_b.py b/tests/tests_pipeline_b.py
index e69de29..b37b45c 100644
--- a/tests/tests_pipeline_b.py
+++ b/tests/tests_pipeline_b.py
@@ -0,0 +1,29 @@
+import pytest
+import cv2
+import numpy as np
+from pipeline_b import star_detector
+
+def test_file_exists_and_is_an_image(tmp_path):
+    file = tmp_path / "image.jpg"
+    tableau_image = np.random.randint(0, 256, (64, 64), dtype=np.uint8)
+    cv2.imwrite(str(file), tableau_image)
+    assert isinstance(star_detector.reading_picture(file), np.ndarray)
+
+def test_file_exists_not_an_image(tmp_path):
+    file = tmp_path / "file.txt"
+    file.write_text("Not an image.")
+    with pytest.raises(ValueError):
+        star_detector.reading_picture(file)
+
+def test_file_does_not_exists(tmp_path):
+    with pytest.raises(FileNotFoundError):
+        star_detector.reading_picture(tmp_path/"do_I_exist.txt")
+
+@pytest.mark.skip(reason="A corriger : égalité stricte sur flottants, canall couleur incohérent, détour disque inutile")
+def test_blob_detector_actually_detects_a_blob(tmp_path):
+    file = tmp_path / "image.jpg"
+    tableau_image = np.full((64,64), 0, dtype=np.uint8)
+    cv2.imwrite(str(file), tableau_image)
+    src = cv2.imread(file)
+    cv2.circle(src, center=(23, 31), radius = 5, color= (255, 255, 255), thickness=-1)
+    assert star_detector.blob_detector(src) == [(23, 31)]
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