Clarify descriptions for mean intensity set point and IR brightness parameters in launch parameters documentation

docs/en/source/camera_devices/4_application_guide/launch_parameters.md

@@ -85,7 +85,7 @@ The following are the launch parameters available:
 
     *   Enable the Depth auto exposure priority.
 *   **`mean_intensity_set_point`**
-    *   Set the target mean intensity of the Depth image. For example: `mean_intensity_set_point:=100`.
+    *   Set the target average intensity of the depth image when auto-exposure is turned on. For example: `mean_intensity_set_point:=100`.
     > **Note:** This replaces the deprecated `depth_brightness`, which is still supported for backward compatibility.
 *   **`enable_depth_scale`**
     *   Whether to enable depth scaling after setting D2C. `true` means enabled, the default is `true`.
@@ -102,8 +102,7 @@ The following are the launch parameters available:
 *   **`ir_ae_max_exposure`**
     *   Set the maximum exposure value for IR auto exposure.
 *   **`ir_brightness`**
-    *   Set the IR brightness.
-
+    *   Set the target average intensity of the ir image when auto-exposure is turned on.
 #### Laser / LDP
 *   **`enable_laser`**
     *   Enable the laser. The default value is `true`.

docs/zh/source/camera_devices/4_application_guide/launch_parameters.md

@@ -84,7 +84,7 @@
 *   **`enable_depth_auto_exposure_priority`**
     *   启用深度自动曝光优先级。
 *   **`mean_intensity_set_point`**
-    *   设置深度图像的目标平均强度。例如：`mean_intensity_set_point:=100`。
+    *   设置开启自动曝光时深度图像的目标平均强度。例如：`mean_intensity_set_point:=100`。
     > **注意：** 这取代了已弃用的 `depth_brightness`，后者仍支持以保持向后兼容性。
 *   **`enable_depth_scale`**
     *   设置D2C后是否启用深度缩放。`true`表示启用，默认为`true`。
@@ -101,7 +101,7 @@
 *   **`ir_ae_max_exposure`**
     *   设置红外自动曝光的最大曝光值。
 *   **`ir_brightness`**
-    *   设置红外亮度。
+    *   设置开启自动曝光时ir图像的目标平均强度。
 
 #### 激光 / LDP
 *   **`enable_laser`**