DICOM Imaging Operations

DICOM Imaging Operations

This documentation provides a step-by-step guide on how to render images (frames) stored in a DICOM file using the Aspose.Medical library. The Aspose.Medical.Dicom API allows us to load a DICOM file and render individual frames as raw images for further processing or display.

Checking the Number of Frames

DICOM files may contain multiple frames (e.g., for CT or MRI scans). To determine how many frames are present, use the NumberOfFrames property.

// Load DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

int frameCount = dicomFile.NumberOfFrames;
System.Console.WriteLine($"Total Frames in DICOM file: {frameCount}");

This information helps decide which frame to render.

Rendering a Single Frame as an Image

The Aspose.Medical.Dicom.DicomFile.RenderImage() method allows rendering a single image (frame) from the DICOM file. By default, it renders the first frame (index 0).

// Load DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

Aspose.Medical.Imaging.IRawImage rawImage = dicomFile.RenderImage(0);

The Aspose.Medical.Imaging.IRawImage contains image pixel data (in BGRA-32 format), dimensions, and color information.

Accessing Image Properties

After rendering, we can inspect the generated image details:

int width = rawImage.Width;
int height = rawImage.Height;

System.Console.WriteLine($"Rendered Frame Dimensions: {width} x {height}");

This gives us the size of the rendered image.

Accessing Pixel Values

Aspose.Medical.Imaging.PixelFormats.Bgra32 pixelColor = rawImage[10, 10]; // Get pixel at (10,10)
System.Console.WriteLine($"Pixel at (10,10): R={pixelColor.R}, G={pixelColor.G}, B={pixelColor.B}");

This can be useful for image analysis or displaying pixels with custom processing.

Rendering a Specific Frame

If the DICOM file contains multiple frames, we can specify which frame to render by its zero-based index.

// Load DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

 // Render the frame # 43 (index 42)
int frameIndex = 42;
Aspose.Medical.Imaging.IRawImage rawImage = dicomFile.RenderImage(frameIndex);

This is useful for multi-frame modalities like CT and MRI scans.

Rendering a Frame with Custom Options

We can customize the rendering process using Aspose.Medical.Dicom.Imaging.Options.RenderOptions. These options control:

  • Overlay visibility
  • Overlay color

To render image with Overlays Disabled please use the following snippet:

// Load DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

Aspose.Medical.Dicom.Imaging.Options.RenderOptions options = new()
{
    ShowOverlays = true,  // Ensure overlays are visible
    OverlayColor = Aspose.Medical.Imaging.PixelFormats.Bgra32.Black, // Set overlay color to black
};

Aspose.Medical.Imaging.IRawImage rawImage = dicomFile.RenderImage(options, 0);

Iterating Over All Frames in a Multi-Frame DICOM File

Some DICOM files contain multiple image frames. You can iterate over all frames using DicomFile.NumberOfFrames and render each one sequentially.

Steps:

  1. Open the DICOM file.
  2. Determine the total number of frames using NumberOfFrames.
  3. Loop through each frame and render it using RenderImage(int frameIndex).
// Open the DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

// Get the total number of frames in the DICOM file
int totalFrames = dicomFile.NumberOfFrames;
Console.WriteLine($"Total Frames: {totalFrames}");

// Iterate over all frames and render each one
for (int i = 0; i < totalFrames; i++)
{
    IRawImage image = dicomFile.RenderImage(i);
    Console.WriteLine($"Rendered Frame {i + 1}: {image.Width}x{image.Height}");
}

Accessing Raw Pixel Data

To access the array with the raw values of image data you can use Aspose.Medical.Dicom.Imaging.PixelData class. Please use the following snippet to access raw image data:

// Open the DICOM file
Aspose.Medical.Dicom.DicomFile dicomFile = DicomFile.Open("path/to/dicom-file.dcm");

// Reads pixel data from Dataset
Aspose.Medical.Dicom.Imaging.PixelData pixelData = PixelData.Read(dicomFile.Dataset);

// Raw image data available using GetRawData method.
System.Span<byte> rawImageData = pixelData.GetRawData();
Data manipulation Transcoding DICOM file