predithering JPEG image for iliad

BACbKA · 02-22-2007, 09:24 AM

Say, I have a JPEG photo image with lots of colours. Grayscale or colour one. When I load it on Iliad it looks pretty ugly. Is there a smart color reducing / predithering linux pipeline that image gurus out there could advice? Manual tweaks in gimp are not welcome, but I can do it as a last resort. Can ImageMagick convert(1) be told about what the iliad's palette is?

b_k · 02-22-2007, 10:48 AM

man ImageMagick :-P

I have to say i never used IM. but this could prove helpful:

Quote:

-map filename

choose a particular set of colors from this image.

[convert or mogrify].

By default, color reduction chooses an optimal set of colors that best represent the original image. Alternatively, you can choose a particular set of colors from an image file with this option.

Source: http://www.imagemagick.org/script/co...ne-options.php

mtas · 02-23-2007, 02:43 AM

Quote:

Originally Posted by BACbKA

Say, I have a JPEG photo image with lots of colours. Grayscale or colour one. When I load it on Iliad it looks pretty ugly. Is there a smart color reducing / predithering linux pipeline that image gurus out there could advice? Manual tweaks in gimp are not welcome, but I can do it as a last resort. Can ImageMagick convert(1) be told about what the iliad's palette is?

I don't know about the quality but sunning convert with the arguments -colorspace GRAY and -colors 16 as arguments should do it.

BACbKA · 02-23-2007, 08:05 AM

Quote:

don't know about the quality but sunning convert with the arguments -colorspace GRAY and -colors 16

-colors 16

reduces the palette to <= 16 colors, but not necessarily THE 16 colors available on iliad! the -map option advised by b_k was what I initially thought of myself, but it requires an image with a correct palette in it to start with as a map.

b_k · 02-23-2007, 12:18 PM

so whats the problem? ask iRex for a BMP. I would think they have one.

BACbKA · 02-23-2007, 04:06 PM

so I guess I am asking them and anyone else who's got it set up already...

b_k · 02-24-2007, 08:48 AM

OTOH, you could try to create a palette by yourself with GIMP. The supported colors are mentioned in the "How to create content ..." document from iRex.

Adam B. · 03-23-2007, 01:43 PM

I'm attaching the pinlock file included in the ipdf sources. If you have imagemagick installed on your computer, you should be able to use the following command to convert it to a color map that best matches the iLiad.

Code:

convert -dither -map pincode_lock_background.png original_image.jpg updated_image.jpg

BACbKA · 04-05-2007, 06:09 PM

Thanks for posting the PNG. Unfortunately, neither your command line, nor the same with the addition of -colorspace GRAY -colors 16 improved anything with my photo

The resulting picture looks great on my PC display, yet looks ugly, with visible added edges at color boundaries, on the iliad. Dithering doesn't seem to visibly help a lot...

02-22-2007, 09:24 AM	#1
BACbKA мокрец Posts: 52 Karma: 28 Join Date: Jan 2007 Location: Israel Device: palm, iliad	predithering JPEG image for iliad Say, I have a JPEG photo image with lots of colours. Grayscale or colour one. When I load it on Iliad it looks pretty ugly. Is there a smart color reducing / predithering linux pipeline that image gurus out there could advice? Manual tweaks in gimp are not welcome, but I can do it as a last resort. Can ImageMagick convert(1) be told about what the iliad's palette is?

03-23-2007, 01:43 PM	#8
Adam B. Addicted to Porting Posts: 1,697 Karma: 7194 Join Date: Oct 2006 Location: Indianapolis, IN Device: iRex iLiad, Nokia 770, Samsung i760	I'm attaching the pinlock file included in the ipdf sources. If you have imagemagick installed on your computer, you should be able to use the following command to convert it to a color map that best matches the iLiad. Code: convert -dither -map pincode_lock_background.png original_image.jpg updated_image.jpg Attached Thumbnails

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02-23-2007, 12:18 PM	#5
b_k Übernerd Posts: 238 Karma: 74 Join Date: Jun 2006 Location: Germany Device: iRex iLiad	so whats the problem? ask iRex for a BMP. I would think they have one.

02-23-2007, 04:06 PM	#6
BACbKA мокрец Posts: 52 Karma: 28 Join Date: Jan 2007 Location: Israel Device: palm, iliad	so I guess I am asking them and anyone else who's got it set up already...

02-24-2007, 08:48 AM	#7
b_k Übernerd Posts: 238 Karma: 74 Join Date: Jun 2006 Location: Germany Device: iRex iLiad	OTOH, you could try to create a palette by yourself with GIMP. The supported colors are mentioned in the "How to create content ..." document from iRex.

04-05-2007, 06:09 PM	#9
BACbKA мокрец Posts: 52 Karma: 28 Join Date: Jan 2007 Location: Israel Device: palm, iliad	Thanks for posting the PNG. Unfortunately, neither your command line, nor the same with the addition of -colorspace GRAY -colors 16 improved anything with my photo The resulting picture looks great on my PC display, yet looks ugly, with visible added edges at color boundaries, on the iliad. Dithering doesn't seem to visibly help a lot...

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