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#1 Posted : Friday, July 18, 2008 11:21:19 PM(UTC)


Groups: Registered
Posts: 17

Environment :
 - Leadtools V15 Medical Suite
 - Visual Basic .Net 2005

I load 16bit TIFF type image.
It was displayed almost black.

After run ApplyLinearVoiLut or HistogramEqualizer , It was shown correctly as I guess

I get pixel value of each pixels in this image by using MinMaxValuesCommand
                 Dim cmd As CopyRectangleCommand = New CopyRectangleCommand
                cmd.Rectangle = New Rectangle(x, y, 1, 1)
                Dim RImg As RasterImage = cmd.DestinationImage.Clone
                RImg.HighBit = Img.HighBit
                Dim cmd2 As MinMaxValuesCommand = New MinMaxValuesCommand

This code returns the value(0~4095) correctly

What is problem ? Why was Image shown so dark ?
What is the effect of ApplyLinearVoiLookupTableCommand?

I will attatch original image(TIFF) and send e-mail to support@leadtools.com linked this post

I need your help
Thank you.


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#2 Posted : Friday, July 18, 2008 11:40:53 PM(UTC)


Groups: Registered
Posts: 17

I Sent e-mail

[Ticket#: 2008071910000115]

#3 Posted : Sunday, July 20, 2008 5:26:47 AM(UTC)

Adnan Ismail  

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Posts: 3,022

Was thanked: 2 time(s) in 2 post(s)

The range 0 to 4095 indicates the data is stored in the lower 12-bits of the image. This means the higher 4 bits are all zero.
When you treat the image as 16-bit, all the values are in the lower 6.25% of the grayscale range. In other words, all the lighter shades (4096 to 65535) are all missing from the image. Since the image only has the dark gray shades, it will appear almost black.

When you modify its histogram using some image processing functions, its gray shades will be expanded to fill a bigger part of the 16-bit range (0 to 65535), and you will see the bright area.

The ApplyLinearVoiLookupTableCommand Class does not modify the pixel data, but translates the intensify values from the 12-bit range to a different range based on the values you pass to the command.

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