OpenCV Integration

Utilities for interoperability between NeoAPI and OpenCV. More...

Namespaces
namespace	opencv
	Provides utilities for interoperability between NeoAPI and OpenCV.

Functions
cv::Mat	irsol::opencv::convertNeoImageToCvMat (const NeoAPI::Image &image)
	Converts a NeoAPI::Image (Mono12, non-packed) into an OpenCV cv::Mat.
cv::Mat	irsol::opencv::createCvMatFromIrsolServerBuffer (unsigned char *data, size_t rows, size_t cols)
	Creates an OpenCV cv::Mat from a raw buffer received from the IRSOL server.

Detailed Description

Utilities for interoperability between NeoAPI and OpenCV.

This group contains functions and types that facilitate the conversion of Baumer NeoAPI images to OpenCV cv::Mat objects. The group is only available if the OpenCV library is found on the user's computer at compilation time. If OpenCV is not detected, this header and its contents are excluded from the build.

Function Documentation

convertNeoImageToCvMat()

cv::Mat irsol::opencv::convertNeoImageToCvMat

(

const NeoAPI::Image &

image

)

Converts a NeoAPI::Image (Mono12, non-packed) into an OpenCV cv::Mat.

Parameters

image

The NeoAPI::Image to convert containing 12-bit grayscale pixel data. Must be in unpacked Mono12 format (2 bytes per pixel, little endian).

Returns

A cv::Mat of type CV_16UC1 with pixel values in range [0, 65535] (pixel raw values from the NeoAPI::Image 12bit depth are rescaled, so that 0 maps to 0 and 2^12-1 (=4095) maps to 2^16-1 (=65535))

Note

The function assumes the NeoAPI::Image is valid and has an appropriate pixel format compatible with OpenCV.

Definition at line 12 of file opencv.cpp.

{
  const size_t width     = image.GetWidth();
  const size_t height    = image.GetHeight();
  const size_t numPixels = width * height;
 
  IRSOL_ASSERT_ERROR(
    image.GetPixelFormat() == NeoAPI::NeoString("Mono12"),
    "Only 'Mono12' pixel format are supported, got '%s'",
    image.GetPixelFormat().c_str());
 
  IRSOL_ASSERT_ERROR(image.GetImageData() != nullptr, "Image data is null");
  IRSOL_ASSERT_ERROR(
    image.GetSize() == numPixels * 2, "Invalid image size for Mono12 unpacked format");
 
  // Raw image data as bytes
  const uint8_t* rawData = reinterpret_cast<const uint8_t*>(image.GetImageData());
 
  // Output Mat with 16-bit unsigned pixels
  cv::Mat                                   output(height, width, CV_16UC1);
  irsol::camera::Pixel<16>::representation* outputPtr =
    output.ptr<irsol::camera::Pixel<16>::representation>();
  for(size_t i = 0; i < numPixels; ++i) {
    // Each pixel takes 2 bytes: LSB + MSB (little endian), we make sure to mask the top 4 bits,
    // even if the should already be 0
    irsol::camera::Pixel<16>::representation value =
      (static_cast<irsol::camera::Pixel<16>::representation>(rawData[2 * i]) |
       (static_cast<irsol::camera::Pixel<16>::representation>(rawData[2 * i + 1]) << 8)) &
      0x0FFF;
    // rescale to map [0, 4095] → [0, 65535] from the 12bit depth to the 16bit depth representation
    outputPtr[i] = irsol::camera::PixelConversion<12, 16>::scale(value);
  }
 
  return output;
}

createCvMatFromIrsolServerBuffer()

cv::Mat irsol::opencv::createCvMatFromIrsolServerBuffer	(	unsigned char *	data,
		size_t	rows,
		size_t	cols
	)

Creates an OpenCV cv::Mat from a raw buffer received from the IRSOL server.

This function takes a pointer to a buffer containing image data in unpacked Mono12 format (2 bytes per pixel, little endian, with bytes for each pixel swapped as sent by the server), and constructs a cv::Mat of type CV_16UC1. The function swaps the bytes for each pixel to match OpenCV's expected order, copies the data into the matrix, and rescales the pixel values from 12-bit depth ([0, 4095]) to 16-bit depth ([0, 65535]).

Parameters

data	Pointer to the raw image buffer. The buffer must contain at least rows * cols * 2 bytes. The data is modified in-place to swap bytes for each pixel.
rows	Number of image rows (height).
cols	Number of image columns (width).

Returns

A cv::Mat of type CV_16UC1 containing the image data with pixel values rescaled to 16 bits.

Note

The input buffer is modified in-place due to byte swapping.

The function assumes the buffer is in unpacked Mono12 format as sent by the IRSOL server.

See also

irsol::protocol::Serializer::serializeImageBinaryData

irsol::camera::PixelByteSwapper

This function takes a pointer to a buffer containing image data in unpacked Mono12 format (2 bytes per pixel, little endian, with bytes for each pixel swapped as sent by the server), and constructs a cv::Mat of type CV_16UC1. The function swaps the bytes for each pixel to match OpenCV's expected order, copies the data into the matrix, and rescales the pixel values from 12-bit depth ([0, 4095]) to 16-bit depth ([0, 65535]).

Parameters

data	Pointer to the raw image buffer. The buffer must contain at least rows * cols * 2 bytes. The data is modified in-place to swap bytes for each pixel.
rows	Number of image rows (height).
cols	Number of image columns (width).

Returns

A cv::Mat of type CV_16UC1 containing the image data with pixel values rescaled to 16 bits.

Note

The input buffer is modified in-place due to byte swapping.

The function assumes the buffer is in unpacked Mono12 format as sent by the IRSOL server.

Definition at line 68 of file opencv.cpp.

{
  // Create Mat from buffer
  cv::Mat mat(rows, cols, CV_16UC1);
  size_t  expectedSize = rows * cols * 2;  // 2 bytes per pixel for Mono12 unpacked
 
  // Change the order of the bytes as the server sends the data where bytes for a single pixel are
  // swapped and OpenCV expects them in the correct order.
  irsol::camera::PixelByteSwapper<true>()(data, data + expectedSize);
 
  // Copy the data into the cv::Mat
  memcpy(mat.data, data, expectedSize);
 
  // Scale the values from the 12-bit depth to 16-bit depth
  mat *= irsol::camera::PixelConversion<12, 16>::factor;
  return mat;
}