Update objective

Author: Zhi Zhou

notebooks/build_person_directory.ipynb

@@ -15,7 +15,7 @@
    "source": [
     "## Objective\n",
     "\n",
-    " This notebook demonstrates how to build a Person Directory by enrolling multiple faces for each person. Each subfolder in a specified directory represents a different person. The script creates a person for each subfolder and adds all face images within that subfolder to the corresponding person\n",
+    " This notebook demonstrates how to identify faces in an image against a known set of persons. It begins by building a Person Directory, where each subfolder in a specified directory represents an individual. For each subfolder, a person is created and all face images within it are enrolled to that person.\n",
     "\n",
     "| Enrollment | Searching |\n",
     "| :-: | :-: |\n",