propublica/facebook-political-ads

reverse image search via perceptual hashing

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#74 opened on Jun 19, 2018

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help wanted

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Description

it would be really neat to be able to search for ads that use an image (e.g. a news photo or a meme) OR group ads that use the same image.

The way to do this would likely be to -- at some point -- record each image's perceptual hash, then at search time, compare the given image to all images in the DB, returning those that are similar. dhash and phash are both perceptual hashing algorithms, but there may be other good choices.

For instance, hopefully, we could determine which ads use the Distracted Boyfriend meme like this one .

Contributor guide

Research direction
Research perceptual hashing algorithms (dhash, phash). Look into libraries like ImageHash (Python). Plan to compute hashes for each image during ad ingestion. At search time, compare hashes using Hamming distance. Consider indexing strategy for scalability.
Tech stack
python
Domain
dataapi
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-2 days
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PythonBasic image processing
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
50