From 6e589d119359868a4ce13da022192f3237d3419c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=BE=99=E6=BE=B3?= <islong.ao@outlook.com>
Date: Fri, 17 Jan 2025 15:36:32 +0800
Subject: [PATCH] =?UTF-8?q?=E9=9A=94=E4=B8=80=E4=B8=AA=E5=88=A0=E4=B8=80?=
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---
 odm_preprocess.py | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/odm_preprocess.py b/odm_preprocess.py
index 96e7379..86902b4 100644
--- a/odm_preprocess.py
+++ b/odm_preprocess.py
@@ -187,6 +187,21 @@ class ImagePreprocessor:
         self.visualizer.visualize_filter_step(
             self.gps_points, previous_points, "3-Time Group Overlap")
 
+    def filter_alternate_images(self):
+        """按时间顺序隔一个删一个图像来降低密度"""
+        previous_points = self.gps_points.copy()
+
+        # 按时间戳排序
+        self.gps_points = self.gps_points.sort_values('timestamp')
+
+        # 保留索引为偶数的行（即隔一个保留一个）
+        self.gps_points = self.gps_points.iloc[::2].reset_index(drop=True)
+
+        self.visualizer.visualize_filter_step(
+            self.gps_points, previous_points, "4-Alternate Images")
+
+        self.logger.info(f"交替过滤后剩余 {len(self.gps_points)} 个点")
+
     def divide_grids(self) -> Tuple[Dict[tuple, pd.DataFrame], Dict[tuple, tuple]]:
         """划分网格
         Returns:
@@ -270,6 +285,7 @@ class ImagePreprocessor:
             self.cluster()
             self.filter_isolated_points()
             self.filter_time_group_overlap()
+            self.filter_alternate_images()
             grid_points, translations = self.divide_grids()
             self.copy_images(grid_points)
             self.logger.info("预处理任务完成")