Image Compression in an FPGA

R

rickman

Guest
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats
seem rather straightforward to implement. Anyone know of an
implementation of one of these in an HDL? It doesn't need to implement
the entire standard, just enough to generate one image style.

--

Rick
 
rickman <gnuarm@gmail.com> wrote:
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats
seem rather straightforward to implement. Anyone know of an
implementation of one of these in an HDL? It doesn't need to implement
the entire standard, just enough to generate one image style.
Click to expand...

Does it actually need to be compressed, or will wrapping headers around
uncompressed data be enough? All of those have uncompressed formats that
will be accepted by a web browser - that may suffice if you aren't concerned
about bandwidth, and would be easier to implement.

Theo
 
On 7/25/2015 2:19 PM, Theo Markettos wrote:
rickman <gnuarm@gmail.com> wrote:
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats
seem rather straightforward to implement. Anyone know of an
implementation of one of these in an HDL? It doesn't need to implement
the entire standard, just enough to generate one image style.

Does it actually need to be compressed, or will wrapping headers around
uncompressed data be enough? All of those have uncompressed formats that
will be accepted by a web browser - that may suffice if you aren't concerned
about bandwidth, and would be easier to implement.
Click to expand...

Yes, I suspect he can even use a fully uncompressed format like bitmap.
His requirements to be for the format to be "widely supported" which
doesn't indicate how recent the browsers need to be and to produce the
image files with little working memory.

He seems to like SVG which seems to meet the latter requirement well if
meeting the former requirement is a bit fuzzy. It looks like nearly all
browsers currently support SVG but only the more recent versions of some.

He does not seem to be limited to connection bandwidth and has not
indicated his needed update rate. This guy often posts discussion
points without giving details until you offer a solution that does not
meet one of the unmentioned requirements. Looks like SVG may be the way
he goes.

--

Rick
 
"rickman" <gnuarm@gmail.com> wrote in message
news:moufqn$8d1$1@dont-email.me...
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats seem
rather straightforward to implement. Anyone know of an implementation of
one of these in an HDL? It doesn't need to implement the entire standard,
just enough to generate one image style.
Click to expand...

There are lots of JPEG encoders out there. Maybe use one?

Tomas D.
 
On 7/26/2015 5:24 PM, Tomas D. wrote:
"rickman" <gnuarm@gmail.com> wrote in message
news:moufqn$8d1$1@dont-email.me...
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats seem
rather straightforward to implement. Anyone know of an implementation of
one of these in an HDL? It doesn't need to implement the entire standard,
just enough to generate one image style.

There are lots of JPEG encoders out there. Maybe use one?
Click to expand...

Thanks for the advice. I will use it in the spirit it was intended. :)

--

Rick
 
rickman <gnuarm@gmail.com> wrote:
He seems to like SVG which seems to meet the latter requirement well if
meeting the former requirement is a bit fuzzy. It looks like nearly all
browsers currently support SVG but only the more recent versions of some.
Click to expand...

If you're just plotting X/Y then SVG may suffice, if you can make a suitable
wrapper around it.

One other thought - get the browser to do the work. Just emit the data in
whatever format you fancy - JSON is a simple one, but even base64 might work
- and then just include some Javascript that plots it in the browser for
you. There's lots of libraries for that:
http://www.sitepoint.com/15-best-javascript-charting-libraries/
You can just use a URL so don't need the JS framework on the FPGA.

Lots of 'analytics' sites do this - download the table of (eg) share
prices as XML or JSON and plot locally, rather than plotting server-side.
Makes for better interaction too - easier to navigate when your browser has
the dataset.

Theo
 
rickman wrote:
On 7/26/2015 5:24 PM, Tomas D. wrote:
"rickman" <gnuarm@gmail.com> wrote in message
news:moufqn$8d1$1@dont-email.me...
Someone is looking to generate compressed images in an FPGA to display
graph data on a browser. Looking around the GIF, TIFF or PNG formats
seem
rather straightforward to implement. Anyone know of an
implementation of
one of these in an HDL? It doesn't need to implement the entire
standard,
just enough to generate one image style.

There are lots of JPEG encoders out there. Maybe use one?

Thanks for the advice. I will use it in the spirit it was intended. :)
Click to expand...

JPEG is not very good at reproducing line art with high contrast
ratio. For example save a screen capture in TIFF, PNG,
and JPEG and you'll see that JPEG gives the most blurring and
artefacts unless you set it for very little compression. PNG
is quite good at achieving compression on computer-generated
images with text or line drawings.

--
Gabor
 
JPEG is not very good at reproducing line art with high contrast
ratio. For example save a screen capture in TIFF, PNG,
and JPEG and you'll see that JPEG gives the most blurring and
artefacts unless you set it for very little compression. PNG
is quite good at achieving compression on computer-generated
images with text or line drawings.
Click to expand...

The reason I've offered JPEG is because it's available on OpenCores and
tested to work fine. I am not sure if there's PNG encoder anywhere available
for free... And I wonder what's the logic utilization difference.
 
On 8/2/2015 11:28 AM, Tomas D. wrote:
JPEG is not very good at reproducing line art with high contrast
ratio. For example save a screen capture in TIFF, PNG,
and JPEG and you'll see that JPEG gives the most blurring and
artefacts unless you set it for very little compression. PNG
is quite good at achieving compression on computer-generated
images with text or line drawings.

The reason I've offered JPEG is because it's available on OpenCores and
tested to work fine. I am not sure if there's PNG encoder anywhere available
for free... And I wonder what's the logic utilization difference.
Click to expand...

The guy is using SVG which is not only much more highly compressed
compared to JPG, it is *much* easier to produce. I don't think he has
any trouble finding someone to write the code. Even if a core is stated
to be "working", you need to do your due diligence and verify any core
you use. That is often as much work as writing the core.

--

Rick
 
You must log in or register to reply here.

Welcome to EDABoard.com

Sponsor

Back
Top