Magnitude#

Computes magnitude of elements of a complex data image.

Description

This function computes magnitude of elements of the source image src given in complex data format, and stores results in the destination image dst. The element-wise magnitude is defined by the formula:

\[dst_{ijk} = \sqrt{Re(src_{ijk})^2 + Im(src_{ijk}^2)}\]

where

  • \(i,j,k\) are coordinates and color component of the image pixel

  • \(Re(x)\) is real part of value

  • \(Im(x)\) is imaginary part of pixel value

Input type must be a complex number type. Output image type will be of the same layout as input type but with a real number output.

Headers

oneapi/ipl/misc/magnitude.hpp

Syntax

template<typename ComputeT = float, typename SrcImageT, typename DstImageT>
sycl::event oneapi::ipl::magnitude(sycl::queue &queue, SrcImageT &src, DstImageT &dst, const magnitude_spec &spec = {}, const std::vector<sycl::event> &dependencies = {})#

Computes magnitude of elements of a complex data image.

Template Parameters:

  • ComputeT – type to perform calculations

  • SrcImageT – Source image type

  • DstImageT – Destination image type

Parameters:

  • queue – SYCL queue

  • src – source image

  • dst – destination image

  • spec – algorithmic spec

  • dependencies – list of events to wait for before starting computation, if any. if omitted, defaults to no dependencies.

Returns:

SYCL event

Supported values for ComputeT:

float

double

half

✓

✓

✗

Supported combinations for Data types/Layouts:

Supported Input/Output Layouts

plane

channel3

Supported Input data types

std::complex<float>

Supported Output data types

float

Parameters

class magnitude_spec#

Magnitude parameters.

Errors

compile-time memory layout check

Indicates an error when image memory layout is not supported.

compile-time data type check

Indicates an error when image data type is not supported.

compile-time compute data type check

Indicates an error when compute data type is not supported.

invalid_argument exception

Indicates an error when ROI sizes of the source image and the destination image are not equal.

invalid_argument exception

Indicates an error when one of the pitch values is not divisible by size of component data type in bytes.

The code example below demonstrates how oneapi::ipl::magnitude shall be called:

using namespace oneapi;

sycl::queue                 queue;
ipl::shared_usm_allocator_t allocator{ queue };
const sycl::range<2>        image_size{ height, width };

// Source 3-channel complex input image
ipl::image<ipl::layouts::channel3, std::complex<float>> src_image{ queue, p_image_data, image_size, allocator };

// Destination float image
ipl::image<ipl::layouts::channel3, float> dst_image{ image_size, allocator };

const ipl::magnitude_spec mag_spec{};
auto  event = ipl::magnitude(queue, src_image, dst_image, mag_spec);