> I installed tesseract to do some simple OCR on a very basic image - a
> phone number in Arial 11pt in a png format (http://www.autohop.bg/OCR/
> phone.png) which I convert to a uncompressed tiff using:

> Flipz wrote:
> > Hi,

> > I installed tesseract to do some simple OCR on a very basic image - a
> > phone number in Arial 11pt in a png format (http://www.autohop.bg/OCR/
> > phone.png) which I convert to a uncompressed tiff using:

> ...

> If this image is at 300dpi, do you think it is managable for tesseract
> to extract the numbers?

> On Jul 4, 1:10 pm, Yury Tarasievich <yury.tarasiev...@gmail.com>
> wrote:
>> For tesseract to produce something, you'll need
>> an image with a resolution on the order of 100-s
>> of dpi. I find that 300 dpi works
>> satisfactorily, but 200 dpi seems also okay. And
>> you have something like 72 dpi image there.

>Hi,

>I installed tesseract to do some simple OCR on a very basic image - a
>phone number in Arial 11pt in a png format (http://www.autohop.bg/OCR/
>phone.png) which I convert to a uncompressed tiff using:

>convert -monochrome -normalize ./phone.png ./phone.tif

>When I run it through tesseract I get an empty file from the following
>command:

>/usr/bin/tesseract ./phone.tif phone

>I tried training the program but I cant get the whole logic around the
>box files. I only need to detect the numbers in the png. Do I need to
>additionally train tesseract for that or it is built in the current
>eng support? I looked very simple from the tesseract documentation but
>apparently I am missing out on something because I get an empty
>phone.txt file.

>Any help will be appreciated.

>Thanks,

>CJ

> If this image is at 300dpi, do you think it is managable for tesseract
> to extract the numbers?

> > If this image is at 300dpi, do you think it is managable for tesseract
> > to extract the numbers?

> Can't see why not. And upscaling may indeed be
> done with convert or, possibly, Gimp. I can't
> point out the best algorithm for the upscaling,
> however (you know, biliniear, bicubic etc.)

> --

> Thanks for all your help, especially Yury's for pointing me to the
> direction of upscaling the image, I was trying to create a custom
> tesseract box for something already built in the eng distribution of
> the software :)

> On 5 Юли, 10:27, Yury Tarasievich <yury.tarasiev...@gmail.com> wrote:

> > Flipz wrote:
> > > Do you know a way to upscale this png to 300dpi through a Linux
> > > command (maybe in convert?). As far as I know web images are mostly
> > > 72dpi and this means I won't be able to use tesseract for any of them,
> > > correct?

> > > If this image is at 300dpi, do you think it is managable for tesseract
> > > to extract the numbers?

> > Can't see why not. And upscaling may indeed be
> > done with convert or, possibly, Gimp. I can't
> > point out the best algorithm for the upscaling,
> > however (you know, biliniear, bicubic etc.)

> > --

> I run into the same problem as yours. Can you pleas tell me how to
> increase the dpi of an image in linux with convert and how to check
> the dpi of an image with command?

> Thanks

> On Jul 5, 3:37 am, Flipz <svet...@icepique.com> wrote:

> > I did it with convert, it has a very nice set of upscaling algorithms
> > and I managed to pull it off to 300dpi which gives 98%+ accuracy
> > rate..

> > Thanks for all your help, especially Yury's for pointing me to the
> > direction of upscaling the image, I was trying to create a custom
> > tesseract box for something already built in the eng distribution of
> > the software :)

> > On 5 Юли, 10:27, Yury Tarasievich <yury.tarasiev...@gmail.com> wrote:

> > > Flipz wrote:
> > > > Do you know a way to upscale this png to 300dpi through a Linux
> > > > command (maybe in convert?). As far as I know web images are mostly
> > > > 72dpi and this means I won't be able to use tesseract for any of them,
> > > > correct?

> > > > If this image is at 300dpi, do you think it is managable for tesseract
> > > > to extract the numbers?

> > > Can't see why not. And upscaling may indeed be
> > > done with convert or, possibly, Gimp. I can't
> > > point out the best algorithm for the upscaling,
> > > however (you know, biliniear, bicubic etc.)

> > > --- Скриване на цитирания текст -

> - Показване на цитирания текст -

> $phone_image     = "test.png";
> $phone_image_1 = "test_upscale.png";
> $phone_image_2 = "test_upscale.tif";
> $phone_extract   = "test_phone";

> exec("/usr/bin/convert -filter Lanczos -resample 300x300 -enhance ".
> $phone_image." ".$phone_image_1);
> exec("/usr/bin/convert -monochrome -normalize ".$phone_image_1." ".
> $phone_image_2);
> exec("/usr/bin/tesseract ".$phone_image_2." ".$phone_extract);

> On 8 Юли, 18:44, zhi <simonz...@gmail.com> wrote:

> > Hi Flipz,

> > I run into the same problem as yours. Can you pleas tell me how to
> > increase the dpi of an image in linux with convert and how to check
> > the dpi of an image with command?

> > Thanks

> > On Jul 5, 3:37 am, Flipz <svet...@icepique.com> wrote:

> > > I did it with convert, it has a very nice set of upscaling algorithms
> > > and I managed to pull it off to 300dpi which gives 98%+ accuracy
> > > rate..

> > > Thanks for all your help, especially Yury's for pointing me to the
> > > direction of upscaling the image, I was trying to create a custom
> > > tesseract box for something already built in the eng distribution of
> > > the software :)

> > > On 5 Юли, 10:27, Yury Tarasievich <yury.tarasiev...@gmail.com> wrote:

> > > > Flipz wrote:
> > > > > Do you know a way to upscale this png to 300dpi through a Linux
> > > > > command (maybe in convert?). As far as I know web images are mostly
> > > > > 72dpi and this means I won't be able to use tesseract for any of them,
> > > > > correct?

> > > > > If this image is at 300dpi, do you think it is managable for tesseract
> > > > > to extract the numbers?

> > > > Can't see why not. And upscaling may indeed be
> > > > done with convert or, possibly, Gimp. I can't
> > > > point out the best algorithm for the upscaling,
> > > > however (you know, biliniear, bicubic etc.)

> > > > --- Скриване на цитирания текст -

> > - Показване на цитирания текст -