Database design to store image color pattern in MySQL for searching Image by color

Question

I am building a image galley using PHP and MySQL where I want to implement Image search by it's color. By following Imagick::getImageHistogram i got the most presented colors from the images.

<?php
$image = new Imagick("thing.png");
$pixels=$image->getImageHistogram();
foreach($pixels as $p){
 $colors = $p->getColor();
 foreach($colors as $c){
        print( "$c\t" );
 }
 print( "\t:\t" . $p->getColorCount() . "\n" );
}
?>

This will print out something like:

Red    Green    Blue       Alpha    :    No of times appeared
252    250      252        1        :       125
194    156      182        1        :       126
109    18       79         1        :       11440
2      117      162        1        :       12761
255    255      255        1        :       40769

Although I am done with getting the colors, I am stuck with designing the database to store the color information along with image path in the database.

My question is how to design a database (table structure) to store this kind of data where search can query can be applied in an effective manner.

Update:

Secondly how can I get the images with a matching color. Let's say user is searching for a color #ff0000, then how can I get all the nearest matched images from the database.

Thank You

Answer 1

You should normalize this.

3 Tables:

Image {image_id, name}
Colors {color_id, red, green, blue, alpha}
ImageHasColor {image_id, color_id, number_of_times_appeared}

Inserting data should be simple, use ...insert_id functions to get the id from the row you just inserted.

Select with joins like:

SELECT * FROM
Image i
JOIN ImageHasColors h
ON i.image_id = h.image_id
JOIN Colors c
ON c.color_id = h.color_id
ORDER BY i.image_id

Check this link on how to convert HEX color to RGB values: http://bavotasan.com/2011/convert-hex-color-to-rgb-using-php/

Search top 10 really red pictures:

SELECT * FROM
Image i
JOIN ImageHasColors h
ON i.image_id = h.image_id
JOIN Colors c
ON c.color_id = h.color_id
WHERE c.red > 200
AND   c.green < 50
AND   c. green < 50
ORDER BY h.number_of_times_appeared
LIMIT 10

Search rather black pictures:

SELECT * FROM
Image i
JOIN ImageHasColors h
ON i.image_id = h.image_id
JOIN Colors c
ON c.color_id = h.color_id
WHERE c.red < 30
AND   c.green < 30
AND   c. green < 30
ORDER BY h.number_of_times_appeared
LIMIT 10