UpdatePixPaddingSettingsFrom Method

Description:

Sets the Pixel Padding Value that is used to display 16-bit grayscale image.

Here is a description of what this Data Element is used and how ImageGear implements this using: DICOM images sometimes contain a Data Element called "Pixel Padding Value" (PPV). The PPV is used mostly to fill in the corners of round images. DICOM provides a Tag for PPV of (0028,0120). This Data Element stores a 16-bit grayscale value that is to be treated as the Pixel Padding Value. Any pixels in the image that have this value are not to be treated as meaningful objects but as background color. Pixel Padding Value is most often set to a very large or very small value and therefore it can be easily differentiated from the real pixel values.

When ImageGear Medical loads a DICOM image that contains a PPV, the value is captured and stored in the IGPage Object. In fact, 3 values are stored: the PPV from the PPV Data Element, a flag indicating that a PPV was found in the file when it was loaded, and an 8-bit grayscale value used to display pixels with this value. UpdatePixPaddingSettingsFrom can alter the values of these in-memory copies of the PPV data.

When UsePixPadding Property is set to True, pixels from the original image equal to the PPV are treated as background. All functions that fill the 16x8 LUT will skip this value and place the DisplayPpvAs value in the PPV slot of the table. This allows an application to adjust the contrast of the image while keeping the PPV or background constant. The background is displayed with a grayscale value equal to that stored in DisplayPpvAs. The PPV is also used for the IP algorithms. Methods like IGMedPage.Processing.GetMinMax Method ignore pixel values that are equal to the PPV. (See below).

UsePixPadding Property is initially set to True if the loaded image contains a Pixel Padding Value Data Element (0028,0120). If a PPV Data Element isn't found, UsePixPadding is initially set to False.

PixPaddingVal is initially set to the Data Field of the Pixel Padding Value Data Element (0028,0120) if it is found. If there is no PPV Data Element, it is set to 0. DisplayPpvAs is not a part of the PPV Data Element. This value is initially set to default value of 64.

When the UsePixPadding Property == True the medical image processing methods, such as Processing.GetMinMax Method or Processing.TabulateHistogram16Gray Method, ignore the Pixel Padding Value. Pixel Padding Value is used for the borders of the image rather than for the actual image, and therefore it should not be taken into account in calculation of the image statistics.

To retrieve the Pixel Padding Value that is currently stored memory call GetPixPaddingSettings Method.

Syntax:

      UpdatePixPaddingSettingsFrom(pPixPadSettings As
IGMedPixPaddingSettings)

Parameters:

Name	Description
pPixPadSettings	New pixel padding settings

Return Value:

N/A

Bits Per Pixel:

9..16

Sample:

Med