This class implements functions interpolating frames and image content. More...

Public Types
enum	InterpolationMethod { IM_INVALID , IM_NEAREST_PIXEL , IM_BILINEAR }
	Definition of individual interpolation methods. More...

enum	ResizeMethod { RM_INVALID , RM_NEAREST_PIXEL , RM_BILINEAR , RM_NEAREST_PYRAMID_LAYER_11_BILINEAR , RM_NEAREST_PYRAMID_LAYER_14641_BILINEAR , RM_AUTOMATIC = RM_NEAREST_PYRAMID_LAYER_11_BILINEAR }
	Definition of individual resize methods. More...

Static Public Member Functions
static bool	resize (Frame &frame, const unsigned int width, const unsigned int height, const ResizeMethod resizeMethod=RM_AUTOMATIC, Worker *worker=nullptr)
	Resizes/rescales a given frame by application of a specified interpolation method. More...

static bool	resize (const Frame &source, Frame &target, const ResizeMethod resizeMethod=RM_AUTOMATIC, Worker *worker=nullptr)
	Resizes/rescales a given frame by application of a specified interpolation method. More...

template<typename T , unsigned int tChannels, ResizeMethod tResizeMethod = RM_AUTOMATIC>
static bool	resize (const T source, T target, const unsigned int sourceWidth, const unsigned int sourceHeight, const unsigned int targetWidth, const unsigned int targetHeight, const unsigned int sourcePaddingElements, const unsigned int targetPaddingElements, Worker *worker=nullptr)
	Resizes/rescales a given 1-plane frame by application of a specified interpolation method. More...

static bool	affine (const Frame &input, Frame &output, const SquareMatrix3 &input_A_output, const InterpolationMethod interpolationMethod=IM_BILINEAR, const uint8_t borderColor=nullptr, Worker worker=nullptr, const PixelPositionI &outputOrigin=PixelPositionI(0, 0))
	Applies an affine transformation to an image (with zipped pixel format). More...

static bool	homography (const Frame &input, Frame &output, const SquareMatrix3 &input_H_output, const InterpolationMethod interpolationMethod=IM_BILINEAR, const uint8_t borderColor=nullptr, Worker worker=nullptr, const PixelPositionI &outputOrigin=PixelPositionI(0, 0))
	Transforms a given input frame (with zipped pixel format) into an output frame (with arbitrary frame dimension) by application of a homography. More...

Static Protected Member Functions
template<typename T , unsigned int tChannels>
static bool	resize (const T source, T target, const unsigned int sourceWidth, const unsigned int sourceHeight, const unsigned int targetWidth, const unsigned int targetHeight, const unsigned int sourcePaddingElements, const unsigned int targetPaddingElements, const ResizeMethod resizeMethod, Worker *worker=nullptr)
	Resizes/rescales a given 1-plane frame by application of a specified interpolation method. More...

Detailed Description

This class implements functions interpolating frames and image content.

In general, this class is just a thin wrapper around the actual implementation based on the desired interpolation method.
Please be aware that all non-template-based functions of this class are intended for prototyping only.
Binary size can increase significantly when using non-template-based functions as the wrapper will add binary size of every interpolation method.
Thus, in case binary size matters, use the template-based functions directly.
For more details and a visual comparisons of the available image resizing methods see https://facebookresearch.github.io/ocean/docs/images/resizing/

See also: FrameInterpolatorBilinear, FrameInterpolatorNearestPixel.

Member Enumeration Documentation

◆ InterpolationMethod

enum Ocean::CV::FrameInterpolator::InterpolationMethod

Definition of individual interpolation methods.

Enumerator
IM_INVALID	An invalid interpolation method.
IM_NEAREST_PIXEL	An interpolation applying a nearest pixel (nearest neighbor) lookup.
IM_BILINEAR	An interpolation applying a bilinear interpolation.

◆ ResizeMethod

enum Ocean::CV::FrameInterpolator::ResizeMethod

Definition of individual resize methods.

Commonly, higher enum values will create better image qualities, while also will need more computational time.

Enumerator
RM_INVALID	An invalid resize method.
RM_NEAREST_PIXEL	An interpolation applying a nearest pixel (nearest neighbor) lookup.
RM_BILINEAR	An interpolation applying a bilinear interpolation.
RM_NEAREST_PYRAMID_LAYER_11_BILINEAR	A two-step interpolation, first applying a pyramid down sampling with a 11 filtering, followed by bilinear interpolation from pyramid layer to target image.
RM_NEAREST_PYRAMID_LAYER_14641_BILINEAR	A two-step interpolation, first applying a pyramid down sampling with a 14641 filtering, followed by bilinear interpolation from pyramid layer to target image.
RM_AUTOMATIC	The resize method with best quality/performance ratio providing high image qualities with good performance values.

Member Function Documentation

◆ affine()

static bool Ocean::CV::FrameInterpolator::affine	(	const Frame &	input,
		Frame &	output,
		const SquareMatrix3 &	input_A_output,
		const InterpolationMethod	interpolationMethod = `IM_BILINEAR`,
		const uint8_t *	borderColor = `nullptr`,
		Worker *	worker = `nullptr`,
		const PixelPositionI &	outputOrigin = `PixelPositionI(0, 0)`
	)

static

Applies an affine transformation to an image (with zipped pixel format).

The output frame must have the same pixel format and pixel origin as the input frame, however the dimension (and position) of the output frame can be arbitrary.
This function allows the creation of an output frame fully covering the input frame (if the position and dimension of the output frame covers the transformation of the affine transformation.
The multiplication of the affine transformation with pixel location in the output image yield their location in the input image, i.e., inputPoint = affineTransform * outputPoint.
The parameter 'outputOrigin' applies an additional translation to the provided affine transformation i.e., input_A_output * create_translation_matrix3x3(outputOrigin.x(), outputOrigin.y()).
Please note that here the affine transformation is specified as a 3-by-3 matrix (in contrast to the more commonly used 2-by-3 matrix) and should take of the form:

Rxx  Ryx  Tx
Rxy  Ryy  Ty
 0    0    1

However, this function disregards the last row completely and only uses the top two rows, i.e., the elements a through f. Information: This function is the equivalent to OpenCV's cv::warpAffine().
Note: For applications running on mobile devices, in order to keep the impact on binary size to a minimum please prefer a specialized transformation function (those that work on image pointers instead of Frame instances).

Parameters

input	The input frame that will be transformed, must be valid
output	The resulting frame after applying the affine transformation to the input frame; pixel format and pixel origin must be identical to input frame; memory of output frame must be allocated by the caller
input_A_output	The affine transform used to transform the given input frame, transforming points defined in the output frame into points defined in the input frame
interpolationMethod	The interpolation method to be used, must be either IM_BILINEAR or IM_NEAREST_PIXEL
borderColor	Color of undefined pixel positions, the size of the buffer must match to the number of channels, nullptr to assign 0x00 to each channel
worker	Optional worker object to distribute the computational load
outputOrigin	The origin of the output frame defining the global position of the output frame's pixel coordinate (0, 0), with range (-infinity, infinity)x(-infinity, infinity)

Returns: True, if succeeded

◆ homography()

static bool Ocean::CV::FrameInterpolator::homography	(	const Frame &	input,
		Frame &	output,
		const SquareMatrix3 &	input_H_output,
		const InterpolationMethod	interpolationMethod = `IM_BILINEAR`,
		const uint8_t *	borderColor = `nullptr`,
		Worker *	worker = `nullptr`,
		const PixelPositionI &	outputOrigin = `PixelPositionI(0, 0)`
	)

static

Transforms a given input frame (with zipped pixel format) into an output frame (with arbitrary frame dimension) by application of a homography.

The output frame must have the same pixel format and pixel origin as the input frame, however the dimension (and position) of the output frame can be arbitrary.
This function allows the creation of an output frame fully covering the input frame (if the position and dimension of the output frame covers the transformation of the homography.
The homography given defines the transformation of output pixels to input pixels (inputPoint = homography * outputPoint).
The 'outputOrigin' parameter simply applies an additional translation onto the provided homography i.e., homography * create_translation_matrix3x3(outputOrigin.x(), outputOrigin.y()).
Information: This function is the equivalent to OpenCV's cv::warpPerspective().

Parameters

input	The input frame that will be transformed, must be valid
output	The output frame resulting by application of the given homography, with same pixel format and pixel origin as the input frame, must be valid
input_H_output	The homography used to transform the given input frame, transforming points defined in the output frame into points defined in the input frame
interpolationMethod	The interpolation method to be used, must be either IM_BILINEAR or IM_NEAREST_PIXEL
borderColor	Color of undefined pixel positions, the size of the buffer must match to the number of channels, nullptr to assign 0x00 to each channel
worker	Optional worker object to distribute the computational load
outputOrigin	The origin of the output frame defining the global position of the output frame's pixel coordinate (0, 0), with range (-infinity, infinity)x(-infinity, infinity)

Returns: True, if succeeded

◆ resize() [1/4]

static bool Ocean::CV::FrameInterpolator::resize	(	const Frame &	source,
		Frame &	target,
		const ResizeMethod	resizeMethod = `RM_AUTOMATIC`,
		Worker *	worker = `nullptr`
	)

static

Resizes/rescales a given frame by application of a specified interpolation method.

Parameters

source	The source frame to resize, must not have a packed pixel format, must be valid
target	Resulting target frame with identical frame pixel format and pixel origin as the source frame, must be valid
resizeMethod	The resize method to be used
worker	Optional worker object used for load distribution, must be valid

Returns: True, if the frame could be resized

See also: FrameType::formatIsPacked().

◆ resize() [2/4]

template<typename T , unsigned int tChannels>

static bool Ocean::CV::FrameInterpolator::resize	(	const T *	source,
		T *	target,
		const unsigned int	sourceWidth,
		const unsigned int	sourceHeight,
		const unsigned int	targetWidth,
		const unsigned int	targetHeight,
		const unsigned int	sourcePaddingElements,
		const unsigned int	targetPaddingElements,
		const ResizeMethod	resizeMethod,
		Worker *	worker = `nullptr`
	)

staticprotected

Resizes/rescales a given 1-plane frame by application of a specified interpolation method.

This template-based implementation ensures that the binary impact is as small as possible.

Parameters

source	The source frame buffer to resize, must be valid
target	The target frame buffer, must be valid
sourceWidth	Width of the source frame in pixel, with range [1, infinity)
sourceHeight	Height of the source frame in pixel, with range [1, infinity)
targetWidth	Width of the target frame in pixel, with range [1, infinity)
targetHeight	Height of the target frame in pixel, with range [1, infinity)
sourcePaddingElements	Optional padding at the end of each source row in elements, with range [0, infinity)
targetPaddingElements	Optional padding at the end of each target row in elements, with range [0, infinity)
resizeMethod	The resize method to be used
worker	Optional worker object used for load distribution

Returns: True, if the frame could be resized

Template Parameters

T	Data type of each pixel channel, e.g., 'uint8_t', 'float'
tChannels	Number of channels of the frame, with range [1, infinity)

◆ resize() [3/4]

template<typename T , unsigned int tChannels, FrameInterpolator::ResizeMethod tResizeMethod>

bool Ocean::CV::FrameInterpolator::resize	(	const T *	source,
		T *	target,
		const unsigned int	sourceWidth,
		const unsigned int	sourceHeight,
		const unsigned int	targetWidth,
		const unsigned int	targetHeight,
		const unsigned int	sourcePaddingElements,
		const unsigned int	targetPaddingElements,
		Worker *	worker = `nullptr`
	)

static

Resizes/rescales a given 1-plane frame by application of a specified interpolation method.

This template-based implementation ensures that the binary impact is as small as possible.

Parameters

source	The source frame buffer to resize, must be valid
target	The target frame buffer, must be valid
sourceWidth	Width of the source frame in pixel, with range [1, infinity)
sourceHeight	Height of the source frame in pixel, with range [1, infinity)
targetWidth	Width of the target frame in pixel, with range [1, infinity)
targetHeight	Height of the target frame in pixel, with range [1, infinity)
sourcePaddingElements	Optional padding at the end of each source row in elements, with range [0, infinity)
targetPaddingElements	Optional padding at the end of each target row in elements, with range [0, infinity)
worker	Optional worker object used for load distribution

Returns: True, if the frame could be resized

Template Parameters

T	Data type of each pixel channel, e.g., 'uint8_t', 'float'
tChannels	Number of channels of the frame, with range [1, infinity)
tResizeMethod	The resize method to be used

◆ resize() [4/4]

static bool Ocean::CV::FrameInterpolator::resize	(	Frame &	frame,
		const unsigned int	width,
		const unsigned int	height,
		const ResizeMethod	resizeMethod = `RM_AUTOMATIC`,
		Worker *	worker = `nullptr`
	)

static

Resizes/rescales a given frame by application of a specified interpolation method.

Parameters

frame	The frame to resize, must not have a packed pixel format, must be valid
width	The width of the resized frame in pixel, with range [1, infinity)
height	The height of the resized frame in pixel, with range [1, infinity)
resizeMethod	The resize method to be used
worker	Optional worker object used for load distribution, must be valid

Returns: True, if the frame could be resized

See also: FrameType::formatIsPacked().

The documentation for this class was generated from the following file:

FrameInterpolator.h

Public Types

Static Public Member Functions

Static Protected Member Functions

Detailed Description

Member Enumeration Documentation

◆ InterpolationMethod

◆ ResizeMethod

Member Function Documentation

◆ affine()

◆ homography()

◆ resize() [1/4]

◆ resize() [2/4]

◆ resize() [3/4]

◆ resize() [4/4]