openomr.php

<?php

	class OpenOMR
	{
		const EDGE = 4;
		const DEBUG = 0;
		const MATRIXROWS = 54;
		const MATRIXCOLS = 38;
		const ERROR_MARGIN = 0.5;

		private $debugFolder;

		private $img;
		private $imgSizeW;
		private $imgSizeH;
		private $imgCelSizeW;
		private $imgCelSizeH;
		private $imgCelCompareSizeW;
		private $imgCelCompareSizeH;

		private function __construct($path) {

			//initialize object
			$this->img = new Imagick();
			$this->readImage($path);

			if (self::DEBUG)
			{
				$this->debugFolder = getdate()[0].'/';
				mkdir($this->debugFolder);
			}

			$this->removeColors();
			if (self::DEBUG) $this->img->writeImage($this->debugFolder.'removeColors.PNG'); 
			$this->adjustImage();
			if (self::DEBUG) $this->img->writeImage($this->debugFolder.'adjustImage.PNG'); 
			$this->removeEdges();
			if (self::DEBUG) $this->img->writeImage($this->debugFolder.'removeEdges.PNG'); 
		}

		public static function getInstance($path) {

			if (!isset($path))
				throw new Exception('Please inform the paths of the marks.');

			return new self($path);
		}

		
		private function readImage($path) {
			$this->img->readImage($path);
		}

		private function removeColors() {
			$imginfo = $this->img->identifyImage();
			if ($imginfo['type'] == 'TrueColor') {
				// remove red from image
				$this->img->separateImageChannel(Imagick::CHANNEL_RED);
			} else {
				// desaturate
				$this->img->modulateImage(100, 0, 100);
			}
		}

		private function adjustImage() {
			$this->img->normalizeImage(Imagick::CHANNEL_ALL);
			$this->img->enhanceImage();
			$this->img->despeckleImage();

			$this->img->blackthresholdImage('#808080');
			$this->img->whitethresholdImage('#808080');
		}

		private function removeEdges() {

			//remove edges and possible skew from image
			$this->img->trimImage(85);
			$this->img->deskewImage(15);
			$this->img->trimImage(85);
			$this->img->setImagePage(0, 0, 0, 0);

			$this->calculateSizes();
		}

		private function calculateSizes() {

			$imginfo = $this->img->identifyImage();
			$this->imgSizeW = $imginfo['geometry']['width'];
			$this->imgSizeH = $imginfo['geometry']['height'];
			
			$this->imgCelSizeW = $this->imgSizeW/self::MATRIXCOLS;
			$this->imgCelSizeH = $this->imgSizeH/self::MATRIXROWS;

			$this->imgCelCompareSizeW = $this->imgCelSizeW - ( self::EDGE * 2 );
			$this->imgCelCompareSizeH = $this->imgCelSizeH - ( self::EDGE * 2 );

			if (self::DEBUG) print_r($this);

		}

		private function getRegionFromImage($row, $col) {
			$sizeW = $this->imgCelCompareSizeW;
			$sizeH = $this->imgCelCompareSizeH;
			$pX = ($col * $this->imgCelSizeW)+self::EDGE;
			$pY =  ($row * $this->imgCelSizeW)+self::EDGE;

			if (self::DEBUG) echo "\n" . $col . " - " . $row . " - " . $pX . " - " . $pY;

			return $this->img->getImageRegion($sizeW, $sizeH, $pX, $pY);
		}

		public function getMatrixFromImage() {
			
			// create reference block pattern
			$imageToCompare = new Imagick();
			$imageToCompare->newImage($this->imgCelCompareSizeW, $this->imgCelCompareSizeH, new ImagickPixel('black'));

			$matrixResult = [];

			for ($i = 0; $i < self::MATRIXROWS; $i++)
			{

				for ($j = 0; $j < self::MATRIXCOLS; $j++)
				{
					if (!isset($matrixResult[$i]))
						$matrixResult[$i] = [];


					$regionToCompare = $this->getRegionFromImage($i, $j);

					$regionToCompare->setImagePage(0, 0, 0, 0);

					if (self::DEBUG) $regionToCompare->writeImage($this->debugFolder.$i.'-'.$j.'.PNG'); 

					$imageCompared = $regionToCompare->compareImages($imageToCompare, Imagick::METRIC_ROOTMEANSQUAREDERROR);

					$matrixResult[$i][$j] = $imageCompared[1];

					$regionToCompare->clear();
				}
			}

			$imageToCompare->clear();

			return $matrixResult;
		}


		public function getMarksFromPaths($paths) {
			// create reference block pattern
			$imageToCompare = new Imagick();
			$imageToCompare->newImage($this->imgCelCompareSizeW, $this->imgCelCompareSizeH, new ImagickPixel('black'));

			$result = [];

			foreach ($paths as $path) {

				if (!isset($result[$path['field']])) {
					$result[$path['field']] =	['status' => 0,'value' => '', 'error_margin'=> 1];
				}
				else if ($result[$path['field']]['status'] == 3) {
					//if marked with wrong dont search next path
					continue;
				}
				else if ($result[$path['field']]['status'] == 2) {
					//if a next char from field reset status
					$result[$path['field']]['status'] = 0;
				}
				
				foreach ($path['marks'] as $mark) {

					if ($result[$path['field']]['status'] == 0) {
						$result[$path['field']]['status'] = 1;
					}

					$regionToCompare = $this->getRegionFromImage($mark[0], $mark[1]);

					$regionToCompare->setImagePage(0, 0, 0, 0);

					if (self::DEBUG) $regionToCompare->writeImage($this->debugFolder.$mark[0].'-'.$mark[1].'.PNG'); 

					$differenceBetweenImages = $regionToCompare->compareImages($imageToCompare, Imagick::METRIC_ROOTMEANSQUAREDERROR);

					if ($differenceBetweenImages[1] < $result[$path['field']]['error_margin'])
						$result[$path['field']]['error_margin'] = $differenceBetweenImages[1];

					if ($differenceBetweenImages[1] < self::ERROR_MARGIN)
					{
						//cade doesn't exists difference between black square and region marked concatenate the value
						$result[$path['field']]['value'] .= $mark[2];

						if ($result[$path['field']]['status'] == 2)
						{
							$result[$path['field']]['status'] = 3;
						}
						else
						{
							$result[$path['field']]['status'] = 2;
						}
					};

					$regionToCompare->clear();

				}
			}

			$imageToCompare->clear();

			return $result;
		}

	}