imgsmlr

Overview

breaks on el10

Version

Build

You can build the RPM / DEB packages for imgsmlr using pig build:

pig build pkg imgsmlr         # build RPM / DEB packages

Install

You can install imgsmlr directly. First, make sure the PGDG and PIGSTY repositories are added and enabled:

pig repo add pgsql -u          # Add repo and update cache

Install the extension using pig or apt/yum/dnf:

pig install imgsmlr;          # Install for current active PG version

pig ext install -y imgsmlr -v 18  # PG 18
pig ext install -y imgsmlr -v 17  # PG 17
pig ext install -y imgsmlr -v 16  # PG 16
pig ext install -y imgsmlr -v 15  # PG 15
pig ext install -y imgsmlr -v 14  # PG 14

dnf install -y imgsmlr_18       # PG 18
dnf install -y imgsmlr_17       # PG 17
dnf install -y imgsmlr_16       # PG 16
dnf install -y imgsmlr_15       # PG 15
dnf install -y imgsmlr_14       # PG 14

apt install -y postgresql-18-imgsmlr   # PG 18
apt install -y postgresql-17-imgsmlr   # PG 17
apt install -y postgresql-16-imgsmlr   # PG 16
apt install -y postgresql-15-imgsmlr   # PG 15
apt install -y postgresql-14-imgsmlr   # PG 14

Create Extension:

CREATE EXTENSION imgsmlr;

Usage

imgsmlr: similar images search for PostgreSQL using Haar wavelet transform

The imgsmlr extension implements similar image searching functionality based on Haar wavelet transforms. It provides two data types and functions for converting images into searchable signatures.

CREATE EXTENSION imgsmlr;

Data Types

Functions

Operators

The signature type supports GiST indexing with KNN on the <-> operator.

Example

Create a table of patterns and signatures from JPEG images:

CREATE TABLE pat AS (
    SELECT
        id,
        shuffle_pattern(pattern) AS pattern,
        pattern2signature(pattern) AS signature
    FROM (
        SELECT id, jpeg2pattern(data) AS pattern
        FROM image
    ) x
);

ALTER TABLE pat ADD PRIMARY KEY (id);
CREATE INDEX pat_signature_idx ON pat USING gist (signature);

Search for the top 10 similar images to a given image:

SELECT id, smlr
FROM (
    SELECT
        id,
        pattern <-> (SELECT pattern FROM pat WHERE id = :id) AS smlr
    FROM pat
    WHERE id <> :id
    ORDER BY signature <-> (SELECT signature FROM pat WHERE id = :id)
    LIMIT 100
) x
ORDER BY x.smlr ASC
LIMIT 10;

The inner query selects the top 100 candidates by signature using the GiST index. The outer query refines to the top 10 by pattern distance.