I've installed tesseract-ocr. I was looking at the manual, but i can't see an option that i can define an image bounds (X,Y,W,H)
Can someone help about it , or am asking in a wrong place ?
1 Answer
From the command line, you can run something like this:
tesseract $imageFile $hocr hocr with version 3+ of tesseract.
$imageFile is the input, $hocr = HTML OCR file.
You can parse the file (e.g., with PHP) and get a box for each word. This will help you get the coordinates of every word.
We use this method to make a custom search-able PDF ... We place the text on a page, then overlay the original image. This process can also be simplified with: man hocr2pdf
We then use the classic and lightweight R&OS PDF to build the PDF on the fly with a custom script to rotate the image. I am attaching the updated function (with the updated "stream" function for "resume" support ... Accept-Ranges
class Mpdf extends Cezpdf
{
function addPngFromFile($file,$x,$y,$w=0,$h=0,$angle=0)
{ // read in a png file, interpret it, then add to the system $error=0; $tmp = get_magic_quotes_runtime(); set_magic_quotes_runtime(0); $fp = @fopen($file,'rb'); if ($fp){ $data=''; while(!feof($fp)){ $data .= fread($fp,1024); } fclose($fp); } else { $error = 1; $errormsg = 'trouble opening file: '.$file; } set_magic_quotes_runtime($tmp); if (!$error){ $header = chr(137).chr(80).chr(78).chr(71).chr(13).chr(10).chr(26).chr(10); if (substr($data,0,8)!=$header){ $error=1; $errormsg = 'this file does not have a valid header'; } } if (!$error){ // set pointer $p = 8; $len = strlen($data); // cycle through the file, identifying chunks $haveHeader=0; $info=array(); $idata=''; $pdata=''; while ($p<$len){ $chunkLen = $this->PRVT_getBytes($data,$p,4); $chunkType = substr($data,$p+4,4); switch($chunkType){ case 'IHDR': // this is where all the file information comes from $info['width']=$this->PRVT_getBytes($data,$p+8,4); $info['height']=$this->PRVT_getBytes($data,$p+12,4); $info['bitDepth']=ord($data[$p+16]); $info['colorType']=ord($data[$p+17]); $info['compressionMethod']=ord($data[$p+18]); $info['filterMethod']=ord($data[$p+19]); $info['interlaceMethod']=ord($data[$p+20]); $haveHeader=1; if ($info['compressionMethod']!=0){ $error=1; $errormsg = 'unsupported compression method'; } if ($info['filterMethod']!=0){ $error=1; $errormsg = 'unsupported filter method'; } break; case 'PLTE': $pdata.=substr($data,$p+8,$chunkLen); break; case 'IDAT': $idata.=substr($data,$p+8,$chunkLen); break; case 'tRNS': //this chunk can only occur once and it must occur after the PLTE chunk and before IDAT chunk //print "tRNS found, color type = ".$info['colorType']."<BR>"; $transparency = array(); if ($info['colorType'] == 3) { // indexed color, rbg /* corresponding to entries in the plte chunk Alpha for palette index 0: 1 byte Alpha for palette index 1: 1 byte ...etc... */ // there will be one entry for each palette entry. up until the last non-opaque entry. // set up an array, stretching over all palette entries which will be o (opaque) or 1 (transparent) $transparency['type']='indexed'; $numPalette = strlen($pdata)/3; $trans=0; for ($i=$chunkLen;$i>=0;$i--){ if (ord($data[$p+8+$i])==0){ $trans=$i; } } $transparency['data'] = $trans; } elseif($info['colorType'] == 0) { // grayscale /* corresponding to entries in the plte chunk Gray: 2 bytes, range 0 .. (2^bitdepth)-1 */ $transparency['type']='indexed'; $transparency['data'] = ord($data[$p+8+1]); } elseif($info['colorType'] == 2) { // truecolor /* corresponding to entries in the plte chunk Red: 2 bytes, range 0 .. (2^bitdepth)-1 Green: 2 bytes, range 0 .. (2^bitdepth)-1 Blue: 2 bytes, range 0 .. (2^bitdepth)-1 */ $transparency['r']=$this->PRVT_getBytes($data,$p+8,2); // r from truecolor $transparency['g']=$this->PRVT_getBytes($data,$p+10,2); // g from truecolor $transparency['b']=$this->PRVT_getBytes($data,$p+12,2); // b from truecolor } else { //unsupported transparency type } // KS End new code break; default: break; } $p += $chunkLen+12; } if(!$haveHeader){ $error = 1; $errormsg = 'information header is missing'; } if (isset($info['interlaceMethod']) && $info['interlaceMethod']){ $error = 1; $errormsg = 'There appears to be no support for interlaced images in pdf.'; } } if (!$error && $info['bitDepth'] > 8){ $error = 1; $errormsg = 'only bit depth of 8 or less is supported'; } if (!$error){ if ($info['colorType']!=2 && $info['colorType']!=0 && $info['colorType']!=3){ $error = 1; $errormsg = 'transparancey alpha channel not supported, transparency only supported for palette images.'; } else { switch ($info['colorType']){ case 3: $color = 'DeviceRGB'; $ncolor=1; break; case 2: $color = 'DeviceRGB'; $ncolor=3; break; case 0: $color = 'DeviceGray'; $ncolor=1; break; } } } if ($error){ $this->addMessage('PNG error - ('.$file.') '.$errormsg); return; } if ($w==0){ $w=$h/$info['height']*$info['width']; } if ($h==0){ $h=$w*$info['height']/$info['width']; } // so this image is ok... add it in. $this->numImages++; $im=$this->numImages; $label='I'.$im; $this->numObj++; $options = array('label'=>$label,'data'=>$idata,'bitsPerComponent'=>$info['bitDepth'],'pdata'=>$pdata ,'iw'=>$info['width'],'ih'=>$info['height'],'type'=>'png','color'=>$color,'ncolor'=>$ncolor); if (isset($transparency)){ $options['transparency']=$transparency; } $this->o_image($this->numObj,'new',$options); # $angle in degrees $this->objects[$this->currentContents]['c'].="\nq"; $this->objects[$this->currentContents]['c'].="\n".sprintf('%.3f',$w)." 0 0 ".sprintf('%.3f',$h)." ".sprintf('%.3f',$x)." ".sprintf('%.3f',$y)." cm"; { $this->objects[$this->currentContents]['c'].="\n"."%%angle $angle "; $a = deg2rad((float)$angle); $this->objects[$this->currentContents]['c'].="\n".sprintf('%.6f',cos($a))." ".sprintf('%.6f',sin($a))." ".sprintf('%.6f',-1*sin($a))." ".sprintf('%.6f',cos($a))." 0 0 cm"; } $this->objects[$this->currentContents]['c'].="\n/".$label.' Do'; $this->objects[$this->currentContents]['c'].="\nQ";
}
function stream($options=''){ // setting the options allows the adjustment of the headers // values at the moment are: // 'Content-Disposition'=>'filename' - sets the filename, though not too sure how well this will // work as in my trial the browser seems to use the filename of the php file with .pdf on the end // 'Accept-Ranges'=>1 or 0 - if this is not set to 1, then this header is not included, off by default // this header seems to have caused some problems despite tha fact that it is supposed to solve // them, so I am leaving it off by default. // 'compress'=> 1 or 0 - apply content stream compression, this is on (1) by default if (!is_array($options)){ $options=array(); } if ( isset($options['compress']) && $options['compress']==0){ $tmp = $this->output(1); } else { $tmp = $this->output(); } header("Content-type: application/pdf"); header("Content-Length: ".strlen(ltrim($tmp))); $fileName = (isset($options['Content-Disposition'])?$options['Content-Disposition']:'file.pdf'); header("Content-Disposition: inline; filename=".$fileName); if (isset($options['Accept-Ranges']) && $options['Accept-Ranges']==1){ header("Accept-Ranges: ".strlen(ltrim($tmp))); } echo ltrim($tmp);
}
}
