Combining hough transform and contour algorithm for detecting vehicles' license-plates

Abstract

Vehicle license plate (VLf') recognition is all interestingproblem that has attracted many computer "ision re search groups. Olle of the IIIOst important alld d(jJiclilt task of this problem is VLf' detecting. 11 is 110t only lIsed in V LP recognition systems but also useful to many Irq( fie management systems. Our method is used for the VLP recognition system that deals with Vietnamese I'Ll's and it can also be applied 10 oIlier !)pes of JILl's 11'i/h minor changes.There are variOliS approaches to this problem, slich as texture-based, morphology-based and boundary line based In this paper. we present the boundwJI line-based me/hod Ihat optimizes speed and accl/racy by combining the HOllgh tramjorm and COIl/Ollr algorithm. The en hancement of applying the Hough transform to collfollr images is Ihat the lIIuch improved speed of the algo r/thm. 111 addilion. the algorilhm can be used on VLP images that have been taken from mriOliS distances and have inclined angles betll'een :t30o from the camera. Especially, it C(lll delecl plates in images has more than one VLP. The algorithm was emlliated in two illlage sets with accuracy of about 99% (see 3.3).

Real Time Bangla Vehicle Plate Recognition towards the Need of Efficient Model - A Comprehensive Study

“…Hybrid frameworks, i.e. Hough transform and contour algorithm localizes the number plate to get closed boundaries of the objects and find two interacted parallel lines which are transformed to Hough coordinate to be considered as a plate-candidate [22]. However, there may be images that have other objects such as wear glasses, headlights, decorated things and so on.…”

“…Third stage is the character segmentation based on the color combination and characters position. The final stage is to extract characters recognition using template matching [13], [16,17], neural network [10,11], [21,22,23] or fuzzy classifiers [20] and alike techniques. First two stages is the image processing step and evaluation depends on success rate and error rate.…”

Agent-based Hough Transform: A Way to the Improvement of the Execution Time in the Detection of the Dominant Straight Line in an Image

“…In [10] for example, a description of an algorithm that uses Hough Transform for real-time pattern recognition is made. [9] Presents a boundary line-based method that optimizes speed and accuracy by combining the Hough transform and contour algorithm in vehicles' license-plate recognition. Consequently, Hough Transform technique has seen many improvements in the literature, but always in the context of image processing scope.…”

Design and implementation of real time LPR system on a fixed point DSP

“…There has been considerable interest in detection of the license plate including texture based extraction [9], color based extractions of license plate [1], boundary-line based extraction [2] and Hough transform for line detection [8]. Color based extraction fails if car comes in the same color as the license plate.…”