volcart::PerPixelMap Class Reference

A raster of a UVMap that provides a per-pixel mapping between a Volume and a Texture generated from that volume. More...

#include <vc/core/types/PerPixelMap.hpp>

Collaboration diagram for volcart::PerPixelMap:

Classes
struct	Coord2D
struct	PixelMap

Public Types
using	Pointer = std::shared_ptr< PerPixelMap >

Public Member Functions
auto	operator() (std::size_t y, std::size_t x) const -> const cv::Vec6d &
	Get the mapping for a pixel by x, y coordinate.
auto	operator() (std::size_t y, std::size_t x) -> cv::Vec6d &
	Get the mapping for a pixel by x, y coordinate. More...
auto	getMapping (std::size_t y, std::size_t x) const -> const cv::Vec6d &
	Get the mapping for a pixel by x, y coordinate. More...
auto	getMapping (std::size_t y, std::size_t x) -> cv::Vec6d &
	Get the mapping for a pixel by x, y coordinate. More...
auto	hasMapping (std::size_t y, std::size_t x) const -> bool
	Return whether there is a mapping for the pixel at x, y. More...
auto	getAsPixelMap (std::size_t y, std::size_t x) -> PixelMap
	Get the mapping for a pixel as a PixelMap.
auto	getMappings () const -> std::vector< PixelMap >
	Get a list of valid pixel mappings. More...
auto	getMappingCoords () const -> std::vector< Coord2D >
	Get a list of pixel coordinates with valid mappings. More...
auto	numMappings () const -> std::size_t
	Get the number of valid mappings. More...
void	setDimensions (std::size_t h, std::size_t w)
	Set the dimensions of the map. More...
void	setWidth (std::size_t w)
	Set the width of the map. More...
void	setHeight (std::size_t h)
	Set the height of the map. More...
auto	width () const -> std::size_t
	Get the width of the map.
auto	height () const -> std::size_t
	Get the height of the map.
auto	mask () const -> cv::Mat
	Get the pixel mask.
void	setMask (const cv::Mat &m)
	Set the pixel mask. More...
auto	cellMap () const -> cv::Mat
	Get the cell map image. More...
void	setCellMap (const cv::Mat &m)
	Set the cell map image. More...

Static Public Member Functions
static auto	Crop (const PerPixelMap &map, std::size_t originY, std::size_t originX, std::size_t height, std::size_t width) -> PerPixelMap
	Create a cropped PPM.
static void	WritePPM (const filesystem::path &path, const PerPixelMap &map)
	Write a PerPixelMap to disk.
static auto	ReadPPM (const filesystem::path &path) -> PerPixelMap
	Read a PerPixelMap from disk.

Private Member Functions
void	initialize_map_ ()

Private Attributes
std::size_t	height_ {0}
std::size_t	width_ {0}
OrderedPointSet< cv::Vec6d >	map_
cv::Mat	mask_
cv::Mat	cellMap_
	PerPixelMap ()=default
	Default constructor.
	PerPixelMap (std::size_t height, std::size_t width)
	Constructor with width and height parameters.
auto	initialized () const -> bool
	Return whether the PerPixelMap has been initialized. More...
template<typename... Args>
static auto	New (Args... args) -> Pointer

Detailed Description

A raster of a UVMap that provides a per-pixel mapping between a Volume and a Texture generated from that volume.

Author

Seth Parker

Date

3/17/16

After a segmentation mesh is flattened, the resulting UV space is sampled at a specific resolution in order to generate a texture space (e.g. image). A texturing algorithm is responsible for filtering information from the volume and placing it into this space, the intended result being an image of a manuscript's text. The transformation that maps 2D coordinates in texture space to 3D coordinates in volume space is defined by the per-vertex transformation generated by flattening, however, there are numerous ways that the points between vertices can be mapped back into the volume. Since the calculation of this mapping can be expensive, it is often desirable to perform this operation only once.

The PerPixelMap (PPM) provides a method for storing the result of this calculation. It has the same dimensions as texture space, and each pixel holds the mapped, 3D position for that pixel in volume space. It additionally holds 3 extra double elements, typically used to store the surface normal vector for the 3D position (calculated from the segmentation mesh).

The position and normal vector are stored in a cv::Vec6d: {x, y, z, nx, ny, nz}.

The texturing::PPMGenerator class generates a PerPixelMap by mapping pixels through the barycentric coordinates of the mesh's triangular faces.

Definition at line 49 of file PerPixelMap.hpp.

Member Typedef Documentation

Pointer

using volcart::PerPixelMap::Pointer = std::shared_ptr<PerPixelMap>

Pointer type

Definition at line 84 of file PerPixelMap.hpp.

Member Function Documentation

cellMap()

auto volcart::PerPixelMap::cellMap

(

)

const -> cv::Mat

Get the cell map image.

The cell map contains the face assignment for each pixel in the PPM. This is an optional feature, and older PPMs may not make this information available.

getMapping() [1/2]

auto volcart::PerPixelMap::getMapping	(	std::size_t	y,
		std::size_t	x
	)		-> cv::Vec6d &

Get the mapping for a pixel by x, y coordinate.

getMapping() [2/2]

auto volcart::PerPixelMap::getMapping	(	std::size_t	y,
		std::size_t	x
	)		const -> const cv::Vec6d &

Get the mapping for a pixel by x, y coordinate.

getMappingCoords()

auto volcart::PerPixelMap::getMappingCoords

(

)

const -> std::vector< Coord2D >

Get a list of pixel coordinates with valid mappings.

Convenience function for accessing PPM data as pixel coordinates.

Unlike getMappings(), this function only returns the pixel coordinates which have mappings. Use this function with getMapping() or getAsPixelMap() in high-performance loops:

for(auto [y, x] : ppm.getMappingCoords()) {
    const auto& m = ppm.getMapping(y, x);
    cv::Vec3d pos{m[0], m[1], m[2]};
    cv::Vec3d normal{m[3], m[4], m[5]};
}

getMappings()

auto volcart::PerPixelMap::getMappings

(

)

const -> std::vector< PixelMap >

Get a list of valid pixel mappings.

Convenience function for accessing PPM data as logical pixels with position and normal values. Valid mappings are determined by the PPM's mask.

Warning

This function returns a copy of the valid PPM mappings which can lead to high-memory usage for large PPMs. When memory and performance are important, prefer using getMappingCoords() with getMapping() or getAsPixelMap().

hasMapping()

auto volcart::PerPixelMap::hasMapping	(	std::size_t	y,
		std::size_t	x
	)		const -> bool

Return whether there is a mapping for the pixel at x, y.

Returns true is the pixel mask has not been set or is empty

initialize_map_()

void volcart::PerPixelMap::initialize_map_ ( )

private

Initialize the map for value assignment

Does nothing if either the height or width are 0.

initialized()

auto volcart::PerPixelMap::initialized

(

)

const -> bool

Return whether the PerPixelMap has been initialized.

The map is initialized as soon as its width and height have been set.

New()

template<typename... Args>

static auto volcart::PerPixelMap::New ( Args...  args ) -> Pointer

inlinestatic

Static New function for all constructors of T

Definition at line 95 of file PerPixelMap.hpp.

numMappings()

auto volcart::PerPixelMap::numMappings

(

)

const -> std::size_t

Get the number of valid mappings.

Valid mappings are determined by the number of non-zero pixels in the PPM's mask. If the mask is not set, all pixels are valid.

operator()()

auto volcart::PerPixelMap::operator()	(	std::size_t	y,
		std::size_t	x
	)		-> cv::Vec6d &

Get the mapping for a pixel by x, y coordinate.

setCellMap()

void volcart::PerPixelMap::setCellMap

(

const cv::Mat &

m

)

Set the cell map image.

The cell map contains the face assignment for each pixel in the PPM. This is an optional feature, and older PPMs may not make this information available.

setDimensions()

void volcart::PerPixelMap::setDimensions	(	std::size_t	h,
		std::size_t	w
	)

Set the dimensions of the map.

Warning

Changing the size of the PerPixelMap will clear it of data. Setting either dimension to 0 will result in undefined behavior.

setHeight()

void volcart::PerPixelMap::setHeight

(

std::size_t

h

)

Set the height of the map.

Warning

Changing the size of the PerPixelMap will clear it of data. Setting either dimension to 0 will result in undefined behavior.

setMask()

void volcart::PerPixelMap::setMask

(

const cv::Mat &

m

)

Set the pixel mask.

If the pixel mask is not set or is empty, every pixel is assumed to have a mapping.

Not every pixel in the PerPixelMap will have a mapped value. The pixel mask is an 8bpc, single channel image that indicates which pixels do and do not have mappings. 0 = No mapping, 255 = Has mapping.

setWidth()

void volcart::PerPixelMap::setWidth

(

std::size_t

w

)

Set the width of the map.

Warning

Changing the size of the PerPixelMap will clear it of data. Setting either dimension to 0 will result in undefined behavior.

Member Data Documentation

cellMap_

cv::Mat volcart::PerPixelMap::cellMap_

private

Cell map

Definition at line 275 of file PerPixelMap.hpp.

height_

std::size_t volcart::PerPixelMap::height_ {0}

private

Height of the map

Definition at line 260 of file PerPixelMap.hpp.

map_

OrderedPointSet<cv::Vec6d> volcart::PerPixelMap::map_

private

Map data storage

Definition at line 264 of file PerPixelMap.hpp.

mask_

cv::Mat volcart::PerPixelMap::mask_

private

Pixel mask

The pixel mask is an 8bpc, single channel image that indicates which pixels do and do not have mappings. 0 = No mapping, 255 = Has mapping.

Definition at line 272 of file PerPixelMap.hpp.

width_

std::size_t volcart::PerPixelMap::width_ {0}

private

Width of the map

Definition at line 262 of file PerPixelMap.hpp.

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

• vc/core/types/PerPixelMap.hpp