From 9aef5ba92c8449443f51b2554e059be51383804c Mon Sep 17 00:00:00 2001
From: Matt Hill <matthill@gmail.com>
Date: Thu, 21 Aug 2014 06:21:46 -0400
Subject: [PATCH] Using better interpolation method for deskew.  Added timing

---
 src/openalpr/licenseplatecandidate.cpp | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/openalpr/licenseplatecandidate.cpp b/src/openalpr/licenseplatecandidate.cpp
index 8058a0f..15e998e 100644
--- a/src/openalpr/licenseplatecandidate.cpp
+++ b/src/openalpr/licenseplatecandidate.cpp
@@ -99,6 +99,10 @@ vector<Point2f> LicensePlateCandidate::transformPointsToOriginalImage(Mat bigIma
 
 Mat LicensePlateCandidate::deSkewPlate(Mat inputImage, vector<Point2f> corners)
 {
+  
+  timespec startTime;
+  getTime(&startTime);
+  
   // Figure out the appoximate width/height of the license plate region, so we can maintain the aspect ratio.
   LineSegment leftEdge(round(corners[3].x), round(corners[3].y), round(corners[0].x), round(corners[0].y));
   LineSegment rightEdge(round(corners[2].x), round(corners[2].y), round(corners[1].x), round(corners[1].y));
@@ -130,8 +134,15 @@ Mat LicensePlateCandidate::deSkewPlate(Mat inputImage, vector<Point2f> corners)
   Mat transmtx = getPerspectiveTransform(corners, quad_pts);
 
   // Apply perspective transformation
-  warpPerspective(inputImage, deskewed, transmtx, deskewed.size());
+  warpPerspective(inputImage, deskewed, transmtx, deskewed.size(), INTER_CUBIC);
 
+  if (config->debugTiming)
+  {
+    timespec endTime;
+    getTime(&endTime);
+    cout << "deskew Time: " << diffclock(startTime, endTime) << "ms." << endl;
+  }
+  
   if (this->config->debugGeneral)
     displayImage(config, "quadrilateral", deskewed);