This topic describes how to use the image-related features provided by LinkVisual, including capturing images, searching for images, and specifying the retention period of images.
Prerequisites
An IoT Platform instance of the video type is created and the video device is connected to IoT Platform.
Device-side development
Device-side development is required when your IP camera is directly connected to IoT Platform. For more information, see Device-side development.
Cloud-side development
LinkVisual allows you to call API operations to capture images, search for images, and specify the retention period of images.
Specify the retention period of images
The retention period of images indicates the length of time for which images are retained on IoT Platform. You can call API operations to manage the retention period of images for an IP camera. You can manage the retention period in the following ways:
Call the SetDevicePictureLifeCycle operation to specify the retention period of images from an IP camera.
Call the QueryDevicePictureLifeCycle operation to query the retention period of images from an IP camera.
Capture images
You can use the following methods to capture images:
Call the TriggerCapturePicture operation to trigger image capture on an IP camera and upload the images to IoT Platform.
Enable intelligent image capture that is triggered by alert events. When an IP camera detects specified alert events, it automatically captures images and uploads them to IoT Platform. For more information about the alert events, see Intelligent alerting.
Search for images
LinkVisual allows you to call API operations to search for images by specifying the following conditions.
Time range: You can call the QueryPictureFiles operation to obtain a list of images captured and uploaded by an IP camera within a specified time range.
Image ID: You can call the QueryDevicePictureFile operation to obtain the detailed information about an image with a specified image ID, such as the URL and creation time. You can obtain IDs of all captured images. For more information about how to capture images, see Capture images.
Alert event: You can call the QueryDeviceEventPicture operation to obtain images that are captured and uploaded when the IP camera detects a specified alert event.
Delete images
You can call the DeletePicture operation to delete images from a specified IP camera in batch.
Application-side development
Before you use image-related features, you must complete application-side development. For more information, see Application-side development.