多帧超声 DICOM 文件创建

Question

我是 DICOM 和 DCMTK 的新手。我有一组 BITMAP 超声数据，我想将其保存为无损 DICOM 文件。

在将数据加载到队列frame_queue 并为超声多帧图像设置所有必需的 DICOM 必要参数后，我实现了一个循环以将图像添加到 DcmDataset 中，如下所示：

std::unique_ptr<DcmDataset> dataset;

/*** 
DICOM parameters A setted not added here as many parameters are set
***/


std::shared_ptr<unsigned char[]> frame;
std::shared_ptr<RGBQUAD[]> colorTable;

DJEncoderRegistration::registerCodecs();
DJ_RPLossless params; // codec parameters, we use the defaults
// this causes the lossless JPEG version of the m_dataset to be created
    
/**/
E_TransferSyntax xfer = DcmXfer(EXS_JPEGProcess14).getXfer();
DcmPixelSequence* sequence = new DcmPixelSequence(DcmTag(DCM_PixelData, EVR_OB));
DcmPixelData* newPixelData = new DcmPixelData(DCM_PixelData);
dataset->insert(sequence, OFTrue);

OFstatic_cast(DcmPixelData*, newPixelData)->putOriginalRepresentation(xfer, NULL, sequence);

while (frame_queue.popFrame(frame, colorTable)) // we extract a new frame from the queue
{
    DcmPixelItem* newItem = new DcmPixelItem(DcmTag(DCM_Item, EVR_OB));
    if (newItem != NULL)
    {
        sequence->insert(newItem);
        /* put pixel data into the item */
        std::shared_ptr<Uint8[]> newDCMFrame;
        
        colorTableToRGB(frame, colorTable, newDCMFrame, m_frameWidth, m_frameHeight);
        result = newItem->putUint8Array((Uint8*)newDCMFrame.get(), m_frameHeight * m_frameWidth * 3).good(); // this returns true in my test
        frame.reset();
        colorTable.reset();
    }
}

dataset->chooseRepresentation(EXS_JPEGProcess14, &params); 
dataset->saveFile(path.c_str());

dataset->chooseRepresentation(EXS_JPEGProcess14, &params); 的调用引发错误：

DcmDataset: Wrong class for pixel data element, cannot change representation

DICOM 文件已保存，但为空。

有谁知道是什么导致了这个错误？

Answer 1

只是一个猜测，但您正在以未压缩的表示形式创建数据集。在这种情况下，像素数据不得表示为帧序列。您应该尝试直接在 DcmPixelData 元素上调用 putUint8Array()，而不是向其中插入序列。

当您调用DcmDataset::chooseRepresentation()时，DCMTK 会将这种编码方式更改为您想要直接实现的方式。

对于未压缩的像素数据，不允许使用带有序列的“封装”像素数据编码，我怀疑这就是DcmDataset::chooseRepresentation()抱怨“没有找到预期的东西”的原因。

Answer 2

所以我终于让它工作了：

std::unique_ptr<DcmDataset> dataset;

/*** 
DICOM parameters A setted not added here as many parameters are set
***/


std::shared_ptr<unsigned char[]> frame;
std::shared_ptr<RGBQUAD[]> colorTable;

DJEncoderRegistration::registerCodecs();
DJ_RPLossless params; // codec parameters, we use the defaults
// this causes the lossless JPEG version of the m_dataset to be created
    
/**/
E_TransferSyntax xfer = DcmXfer(EXS_JPEGProcess14).getXfer();

DcmPixelData* newPixelData = new DcmPixelData(DCM_PixelData);
dataset->insert(newPixelData , OFTrue);


bool result = true;
static const int imageSize = m_frameWidth * m_frameHeight * 3;
std::shared_ptr<Uint8[]> imagesBufferPtr(new Uint8[imageSize * m_nbFrames], array_deleter<Uint8>());

std::vector<std::vector<Uint8>> dataImages(m_nbFrames, std::vector<Uint8>(imageSize));

int frameId = 0;

while (this->popFrame(frame, colorTable) == cwlibdicom::frameBufferStatus::BUFFER_SUCCESS && result)
{
    Uint8 *img = imagesBufferPtr.get();
    img = &img[frameId];
    colorTableToRGB(frame, colorTable, img, m_frameWidth, m_frameHeight);

    std::memcpy(&imagesBufferPtr.get()[frameId * imageSize], img.data(), imageSize);

    frameId++;
    frame.reset();
    colorTable.reset();
}
result = newPixelData->putUint8Array(imagesBufferPtr.get(), imageSize * m_nbFrames).good();
header->setProperty(DCM_NumberOfFrames, nb_frame);
header->setProperty(DCM_SamplesPerPixel, "3");
header->setProperty(DCM_PhotometricInterpretation, "RGB");
header->setProperty(DCM_Rows, m_imageHeight);
header->setProperty(DCM_Cols, m_imageWidth);
header->setProperty(DCM_BitsAllocated, "8");
header->setProperty(DCM_BitsStored, "8");
header->setProperty(DCM_HighBit, "7");
header->setProperty(DCM_PixelRepresentation, "0");
header->setProperty(DCM_FrameIncrementPointer, "(0018, 1065)\\(F9E4, 3317)"); // Found this in a multiframe image that already existed.

dataset->chooseRepresentation(EXS_JPEGProcess14, &params); 
dataset->saveFile(path.c_str(), EXS_JPEGProcess14);