Dear Zia,
I may give you a different idea for recovering the plate rectangle that
worked for me.
In my case I had to recover the box contour of a medicine in order to detect
the expiration date in it.
I'm using Leptonica for this:
static const char *seed_sequence = "o3.3 + r11 + o10.1 + c15.10 + x4";
Pix* pix; // the input gray picture
Pix *pixm,*pixM; //the minima and maxima loci
//int w,h;
//pixGetDimensions(pix,&w,&h,NULL);
pixLocalExtrema(pix,0,0,&pixm,&pixM); // to get minima and maxima
Pix *pixMd2 = pixMorphSequence(pixM, seed_sequence, 0); // some cleaning
with opening and closing
float skewAngle,conf;
Pix* pixMdd = pixFindSkewAndDeskew(pixMd2,1,&skewAngle,&conf); // deskew
// find baselines
PTA* pta;
NUMA* numa = pixFindBaselines(pixMdd,&pta,0); // find the horizontal lines
/*numa is an array of ordinates, pta is an array of points (x,y) - the
extreme points of the horizontal lines found for each ordinate. */
Extraxting with a simple logic the key four points ( or just three) of the
main rectangle I build the clipping box.
Among different techniques this was the one more reliable, as the search for
maxima is fairly insensitive to flares and reflections.
Let me know.
Giuseppe
----- Original Message -----
From: "ZIA" <[email protected]>
To: "tesseract-ocr" <[email protected]>
Sent: Monday, August 02, 2010 2:13 AM
Subject: Re: California License Plate font issues with OCR
Thanks Andre for finding the font. I will see how can i use that. As
you suggested using coreldraw, i don't have this software, i will try
to see if i can use some other software like MS word.
I was asking how to extract license plate from image. What I am doing,
i get the image, re-sized, convert to binary image and then run the
sobel edge filter. So now i have an image that shows me the rectangle
part of LP clearly, and I know the ration of height to width is 1 to
2. I just need to scan the image and look for rectangle and calculate
their ration, to get the correct LP from image, or is there any other
more efficient way. I hope this clear things, if not, I will send you
the image as input image and after edge filter image.
Zia
On Jul 31, 9:10 pm, Andres <[email protected]> wrote:
> Anyway, any of you have any idea, about scanning image and getting the
>> LP (image was filtered using edge filter, i can see the rectangle box
>> of LP, just need to figure out, how to scan and how to extract. The
>> ratio of CA LP is 1 to 2, or 6 to 12 inches (height=6, width=12)
>> I'm not sure about being understanding completelly. Could you extend a
little ?
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