summary table to compare between lpg and pd

Author: der3318

articles/ai-services/computer-vision/concept-face-recognition-data-structures.md

@@ -46,15 +46,25 @@ The Face Identify API uses container data structures to the hold face recognitio
 
 **PersonDirectoryPerson** represents a person to be identified. Updated from the **PersonGroupPerson** model, it allows you to add faces from different recognition models to the same person. However, the Identify operation can only match faces obtained with the same recognition model. 
 
-**DynamicPersonGroup** is a lightweight data structure that allows you to dynamically reference a **PersonGroupPerson**. It doesn't require the Train operation: once the data is updated, it's ready to be used with the Identify API.
+**DynamicPersonGroup** is a lightweight data structure that allows you to dynamically reference a **PersonDirectoryPerson**. It doesn't require the Train operation: once the data is updated, it's ready to be used with the Identify API.
 
 You can also use an **in-place person ID list** for the Identify operation. This lets you specify a more narrow group to identify from. You can do this manually to improve identification performance in large groups. 
 
 The above data structures can be used together. For example: 
 - In an access control system, The **PersonDirectory** might represent all employees of a company, but a smaller **DynamicPersonGroup** could represent just the employees that have access to a single floor of the building.
 - In a flight onboarding system, the **PersonDirectory** could represent all customers of the airline company, but the **DynamicPersonGroup** represents just the passengers on a particular flight. An **in-place person ID list** could represent the passengers who made a last-minute change.
 
-For more details, please refer to the [PersonDirectory how-to guide](./how-to/use-persondirectory.md).
+For more details, please refer to the [PersonDirectory how-to guide](./how-to/use-persondirectory.md). A quick comparison between **LargePersonGroup** and **PersonDirectory**:
+
+| Detail | LargePersonGroup | PersonDirectory |
+| --- | --- | --- |
+| Capacity | A **LargePersonGroup** can hold up to 1 million **PersonGroupPerson** objects. | The collection can store up to 20 millions **PersonDirectoryPerson** identities. |
+| PersonURI | `/largepersongroups/{groupId}/persons/{personId}` | `(/v1.0-preview-or-above)/persons/{personId}` |
+| Ownership | The **PersonGroupPerson** objects are exclusively owned by the **LargePersonGroup** they belong to. If you want a same identity kept in multiple groups, you will have to [Create Large Person Group Person](/rest/api/face/person-group-operations/create-large-person-group-person) and [Add Large Person Group Person Face](/rest/api/face/person-group-operations/add-large-person-group-person-face) for each group individually, ending up with a set of person IDs in several groups. | The **PersonDirectoryPerson** objects are directly stored inside the **PersonDirectory**, as a flat list. You can use an in-place person ID list to [Identify From Person Directory](/rest/api/face/face-recognition-operations/identify-from-person-directory), or optionally [Create Dynamic Person Group](/rest/api/face/person-directory-operations/create-dynamic-person-group) and hybridly include a person into the group. A created **PersonDirectoryPerson** object can be referenced by multiple **DynamicPersonGroup** without duplication. |
+| Model | The recognition model is determined by the **LargePersonGroup**. New faces for all **PersonGroupPerson** objects will become associated with this model when they're added to it. | The **PersonDirectoryPerson** object prepares separated storage per recognition model. You can specify the model when you add new faces, but the Identify API can only match faces obtained with the same recognition model, that is associated with the query faces. |
+| Training | You must call the Train API to make any new face/person data reflect in the Identify API results. | There's no need to make Train calls, but API such as [Add Person Face](/rest/api/face/person-directory-operations/add-person-face) becomes a long running operation, which means you should use the response header "Operation-Location" to check if the update completes. |
+| Cleanup | [Delete Large Person Group](/rest/api/face/person-group-operations/delete-large-person-group) will also delete the all the **PersonGroupPerson** objects it holds, as well as their face data. | [Delete Dynamic Person Group](/rest/api/face/person-directory-operations/delete-dynamic-person-group) will only unreference the **PersonDirectoryPerson**. To delete actual person and the face data, see [Delete Person](/rest/api/face/person-directory-operations/delete-person). |
+
 
 ## Data structures used with Find Similar