Resize with Nearest-Neighbor Interpolation

Changes an image size using the Nearest-neighbor interpolation method.

Description

This function changes the image size using the nearest neighbor interpolation method. The image size may be either reduced or increased in each direction, depending on the destination image size. Algorithm parameters must be set through the resize_nearest_spec class. This function can operate with ROI (see Image Regions of Interest).

Headers

oneapi/ipl/transform/resize_nearest.hpp

Syntax

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

Resize with the Nearest-neighbor interpolation method.

Template Parameters:

• ComputeT – type to perform calculations

• SrcImageT – Source image type

• DstImageT – Destination image type

Parameters:

• queue – [in] SYCL queue

• src – [in] source image

• dst – [out] destination image

• spec – [in] algorithmic specification

• dependencies – [in] other events dependencies

Returns:

SYCL event, that represents a status of an operation it associated with

Supported values for ComputeT:

float	double	half
✓	✓	✗

Supported combinations for DataT/Layouts:

DataT/Layouts	plane	channel3	channel4	plane3
std::uint8_t	✓	✓	✓	✗
std::int8_t	✓	✓	✓	✗
std::uint16_t	✓	✓	✓	✗
std::int16_t	✓	✓	✓	✗
std::uint32_t	✓	✓	✓	✗
std::int32_t	✓	✓	✓	✗
float	✓	✓	✓	✗
double	✓	✓	✓	✗

Supported values for subsampled layout (only for std::uint8_t data type):

sub420	sub420i
✗	✗

Parameters

class resize_nearest_spec

Resize nearest 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 one of the pitch values is not divisible by size of component data type in bytes.

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

using namespace oneapi;

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

// Source 4-channel image data
ipl::image<ipl::layouts::channel4, std::uint8_t> src_image{ queue, p_image_data, image_size, allocator };
// Destination 4-channel image data with x2 size
ipl::image<ipl::layouts::channel4, std::uint8_t> dst_image{ image_size * 2, allocator };

auto event = ipl::resize_nearest(queue, src_image, dst_image);