Nike RVSP hashtag extractor

Simple object detection with php. designed for extracting hashtags from nike rvsp images.

<?php

/*
 * Nike RVSP text extractor 
 * Armagan Corlu aka Psy_chip 
 * May 2013 
 * 
 * root@psychip.net
 * 
 */

function GetTextFromImage($filename, $saveto) {
    // working area dimensions
    $xlimit = 375;
    $ylimit = 200;

$im = imagecreatefromjpeg($filename);
    $black = imagecolorallocate($im, 0, 0, 0);
    $green = imagecolorallocate($im, 0, 255, 0);

// make image more readable
    imagefilter($im, IMG_FILTER_BRIGHTNESS, -80);
    imagefilter($im, IMG_FILTER_CONTRAST, -250);
    imagefilter($im, IMG_FILTER_COLORIZE, -255, 0, -255, 0);

// fill areas outside the radius

for ($x = 0; $x < $ylimit; $x++) {
        for ($i = 0; $i < $xlimit; $i++) {
            $rgb = imagecolorat($im, $i, $x);
            $color = imagecolorsforindex($im, $rgb);
            if ($color['green'] > 220) {
                if ($i < 50)
                    imagefill($im, $i, $x, $black);
            }
        }
    }

// Remove Noise

for ($x = 0; $x < $ylimit; $x++) {
        for ($i = 0; $i < $xlimit; $i++) {
            $rgb = imagecolorat($im, $i, $x);
            $color = imagecolorsforindex($im, $rgb);
            if ($color['green'] < 255) {
                imagefill($im, $i, $x, $black);
            }
        }
    }
    
    // safety shot
    imagefill($im, 1, 1, $green);

// detect empty areas
    $maincolor = imagecolorat($im, 1, 1);
    $b_top = 0;
    $b_btm = 0;
    $b_lft = 0;
    $b_rt = 0;

$newimg = imagecreatetruecolor(imagesx($im), $ylimit);
    imagecopy($newimg, $im, 0, 0, 0, 0, imagesx($newimg), $ylimit);
    $im = $newimg;

for (; $b_top < imagesy($im); ++$b_top) {
        for ($x = 0; $x < imagesx($im); ++$x) {
            if (imagecolorat($im, $x, $b_top) != $maincolor) {
                break 2;
            }
        }
    }

for (; $b_btm < imagesy($im); ++$b_btm) {
        for ($x = 0; $x < imagesx($im); ++$x) {
            if (imagecolorat($im, $x, imagesy($im) - $b_btm - 1) != $maincolor) {
                break 2;
            }
        }
    }

for (; $b_lft < imagesx($im); ++$b_lft) {
        for ($y = 0; $y < imagesy($im); ++$y) {
            if (imagecolorat($im, $b_lft, $y) != $maincolor) {
                break 2;
            }
        }
    }

for (; $b_rt < imagesx($im); ++$b_rt) {
        for ($y = 0; $y < imagesy($im); ++$y) {
            if (imagecolorat($im, imagesx($im) - $b_rt - 1, $y) != $maincolor) {
                break 2;
            }
        }
    }

// crop image
    $newimg = imagecreatetruecolor(imagesx($im) - ($b_lft + $b_rt), imagesy($im) - ($b_top + $b_btm));
    imagefill($newimg, 1, 1, $green);
    imagecopy($newimg, $im, 0, 0, $b_lft, $b_top, imagesx($newimg), imagesy($newimg));

// tesseract OCR needs a difference for recognize text, enlarge image a bit
    $border = imagecreatetruecolor(imagesx($newimg) + 10, imagesy($newimg) + 10);
    imagefill($border, 1, 1, $green);
    imagecopy($border, $newimg, 5, 5, 0, 0, imagesx($newimg), imagesy($newimg));
    imagepng($border, $saveto);
}

Size:	3 KB
Date:	18/08/2021
Crc32:	638249516
Modified on:	9 Month ago

Nike RVSP hashtag extractor

August 18, 2021