Image Retrieval: Image Searching with Image

Have you ever wondered how Google image search works?

Fig 1: A screenshot from The Homepage of Google Image.

When you were doing reports, and you want to search for related images, but sometimes you might not know how to describe them with texts, fortunately, you have a few sample images. Google Image allows us to search with images!

Fig 2: Searching steps. (From author; The query image is from here)

Fig 3: Finding details. (From author)

Fig 4: Searching steps. (From author)

In layman's terms, we can use a computer program to find interesting pixels and conclude these pixels as a detail, then sum up all details and find similar images with similar details.

Technically, this is called “Image Retrieval”, which has been studied for a long long time (since the 90s). Not only Google Image, but you can also actually apply the same technique in product search on Amazon (searching product with image), face recognition in Bank verification app (finding your identity over millions of identities), searching for a location…