This topic and its replies were posted before the current version of LEADTOOLS was released and may no longer be applicable.
#1
Posted
:
Wednesday, January 31, 2007 12:54:59 AM(UTC)
Groups: Registered
Posts: 10
I am getting started with 16-bit grayscale image processing using the Medical Imaging toolkit.
<p>
So far, upgrading our existing 8bpp grayscale code (using LEADtools Raster Imaging on Win32 in C++) appears not simple because many functions seem unsupported. Getting invalid parameter errors when calling functions like <b>L_GetFixedPalette</b> (with its nBitsPerPixel argument set to 16) and <b>L_PutBitmapColors</b>
<p>
I am getting the feeling that palettes are not supported at all for 16-bpp images. (Yes, I did unlock the Medical license). There is a group of window leveling functions that do similar things, but these functions don't work for 8bpp grayscales. So there is no way to use similar handling of both 8bpp and 16bpp images, right? Disappointing!<p>
Also L_IsGrayScaleBitmap does not recognize a previously saved 16bpp grayscale image (Windows DIB) as being gray.<p>
L_LoadBitmap fails to load when specifying ORDER_GRAY, so should I really load with ORDER_BGR and then manually poke ORDER_GRAY in the nOrder field of the bitmaphandle?<p>
These matters are not clearly documented in the main API reference manual, I could not find a section dedicated to 12/16-bit grayscale processing, this information is scattered across the help file. Is there an additional document(application note or FAQ?) where I can find the basics of how 16-bpp grayscale images are handled by LEADtools, instead of learning by trial-and-error? <p>
Joost
#2
Posted
:
Wednesday, January 31, 2007 1:05:16 AM(UTC)
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Posts: 10
Sorry, guys. I have no clue how to format my text here, I used HTML tags, which works when previewing the message. But after posting they appear visible and the markup is lost. The forum FAQ tells me to use BBCode markup, but fails to explain that language... and how to actually use those blinking emoticons in the message editor... The forum system is also very slow (response times of more than a minute). Well, if visible is the opposite of invisible then "telligent" must be the opposite of ... [;)]
(edited) [I]
OK, now I have a clue: the message editor seems incompatible with Internet Explorer 7: The toolbars don't appear. On my other PC with IE6 it works normal.
#3
Posted
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Wednesday, January 31, 2007 12:23:46 PM(UTC)
Groups: Registered, Tech Support, Administrators
Posts: 764
16bpp images do use a "palette" but it is called a LUT (Look-Up Table). Most likely, the invalid parameter passed errors are because you're trying to access a palette that doesn't exist. There should be some functions that deal specifically with LUTs, take a look in the help file for these. For many processing functions, you will not be able to use them on 8bpp and 16bpp images, you will need to add some extra logic in your code that checks to see what bpp your image is.
#4
Posted
:
Wednesday, January 31, 2007 11:07:47 PM(UTC)
Groups: Registered
Posts: 10
So the palette functions don't support palettes with more than 256 entries? This is not stated clearly in the API docs.
#5
Posted
:
Friday, February 2, 2007 11:39:40 AM(UTC)
Groups: Registered, Tech Support, Administrators
Posts: 764
Actually it is, you just need to follow a link in the See Also section, namely the article "Handling Palette Changes". This is an extensive article that talks about palettes, and it mentions that they can only have 256 colors or less.
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