This topic describes the concepts that are used in Image Search. The concepts help you familiarize yourself with Image Search before you use the service.
Instance
An instance is an operating unit in the Image Search service. To activate or purchase the Image Search service, you must create one or more instances. Instances provide compute and storage capabilities.
You can use the compute capabilities to extract image characteristics and compare image similarities.
You can use the storage capabilities to store data about image characteristics.
Image Search provides services based on the compute capabilities, the storage capabilities, and the image search engine that is developed by Alibaba Cloud. You can use the Image Search service only after you purchase or create an instance.
QPS
The queries per second (QPS) metric specifies the maximum number of search requests that the Image Search API can process every second. A higher QPS indicates that a larger number of search requests can be processed. If you select 5 Queries/sec for the Queries/sec parameter when you purchase an Image Search instance, you can run a maximum of five image searches within a second.
You can delete a maximum of 20 images every second, regardless of the value of the Queries/sec parameter.
Maximum image capacity
The maximum image capacity specifies the maximum number of images among which you can run searches.
Image gallery
An image gallery is generated based on the images that you upload after you purchase or create an instance. Image searches use image galleries to run searches.
Image import
Image import is the process of uploading images to an image gallery. Image Search provides two import methods: API-based upload and Object Storage Service (OSS) import.
In the API-based upload method, you can call the corresponding API operation to add images. This ensures that the added images can be used for image searches in real time. This method is applicable if you need to add only a small number of images and need to use the added images for image searches in real time.
In the OSS import method, you can import multiple images from an OSS bucket to an image gallery at a time. This method is applicable if you need to import millions or tens of millions of images.
Product category
A product category specifies the group to which a product belongs. When you use the product image search feature, you can determine whether to specify a product category for image additions or searches. If you specify a product category, the system uses the specified category for image searches. If you do not specify a product category, the system automatically predicts product categories. The prediction results are included in the responses.
If you specify a product category, the system searches for images based on the specified scope. This improves search accuracy.
Subject identification
The subject identification feature identifies the subjects in images. You can determine whether to enable the feature when you add or search for images.
If you enable the feature, the system adds or searches for images based on the subject identification results.
If you do not enable the feature, the system adds or searches for images based on all the image content.
The subject identification feature filters out irrelevant background information during image additions and image searches and improves search performance.
Filter condition
A filter condition is a condition that you use to filter data during image searching. You can specify filter conditions and image attributes to filter data. The filter conditions can be connected by the AND or the OR logical operator.