Resize with Bilinear Interpolation

Changes an image size using the linear interpolation method.

Description

This function changes the image size using the linear interpolation method. The image size may be either reduced or increased in each direction, depending on the destination image size. The linear interpolation algorithm must use source image intensities at the four pixels in the neighborhood of the point in the source image. The weighted values of these pixels must be used for the destination image. Algorithm parameters must be set through the resize_bilinear_spec class. The border pixels are processed in accordance with the border type. This function can operate with ROI (see Image Regions of Interest).

Headers

oneapi/ipl/transform/resize_bilinear.hpp

Syntax

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

Resize with the Bilinear 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

border type support

Type of border. Possible values are: repl - Border is replicated from the edge pixels.

class resize_bilinear_spec

Bilinear resize parameters.

Public Functions

resize_bilinear_spec() = default

Construct default spec.

resize_bilinear_spec(border_types border_type)

Construct spec from border type.

Parameters:

border_type – border type

resize_bilinear_spec(crop_types crop)

Construct spec from crop flag.

Parameters:

crop – crop flag

resize_bilinear_spec(border_types border_type, crop_types crop)

Construct spec from border type and crop flag.

Parameters:

• border_type – border type

• crop – crop flag

crop_types get_crop() const noexcept

Returns the crop type.

Returns:

crop type

border_types get_border() const noexcept

Returns the border type.

Returns:

border type

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.
unimplemented exception	Indicates an error when border type is not supported.

The code example below demonstrates how oneapi::ipl::resize_bilinear 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 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_bilinear(queue, src_image, dst_image);