make it harder to select images

fishsense_video_frame_extractor/commands/extract_frames.py

@@ -39,7 +39,7 @@ def update(self, file: Path, frame: int):
 def __diff_images(a: np.ndarray, b: np.ndarray, skip_count: int) -> bool:
     b = cv2.resize(b, (a.shape[1], a.shape[0]), interpolation=cv2.INTER_AREA)
     ssim_score = metrics.structural_similarity(a, b, channel_axis=2)
-    threshold = 0.7 + float(skip_count) / 1500.0
+    threshold = 0.65 + float(skip_count) / 1500.0
     return ssim_score < threshold