org.openimaj.image.pixel.sampling

Enum FLineSampler

java.lang.Object

java.lang.Enum<FLineSampler>

org.openimaj.image.pixel.sampling.FLineSampler

All Implemented Interfaces:

Serializable, Comparable<FLineSampler>, LineSampler<FImage,float[]>

public enum FLineSampler
extends Enum<FLineSampler>
implements LineSampler<FImage,float[]>

Methods for sampling along a line in an FImage.

Author:

Jonathon Hare (jsh2@ecs.soton.ac.uk)

Enum Constant Summary

Enum Constants

Enum Constant and Description
INTERPOLATED Sample the pixel values at regular intervals along the full length of the line using bilinear interpolation to get sub-pixel values.
INTERPOLATED_DERIVATIVE Sample the pixel values at regular intervals along the full length of the line using bilinear interpolation and then compute the derivative using [1 0 -1] filter.
NEAREST_NEIGHBOUR Sample the pixel values at regular intervals along the full length of the line taking the sample value from the nearest pixel.
NEAREST_NEIGHBOUR_DERIVATIVE Sample the pixel values at regular intervals along the full length of the line using nearest-neighbour pixels and then compute the derivative using [1 0 -1] filter.
PIXELSTEP_INTERPOLATED Sample at 1-pixel intervals about the centre of the line using bilinear interpolation to estimate sub-pixel values.
PIXELSTEP_INTERPOLATED_DERIVATIVE Sample at 1-pixel intervals about the centre of the line using bilinear interpolation to estimate sub-pixel values and then compute the derivative using [1 0 -1] filter.
PIXELSTEP_NEAREST_NEIGHBOUR Sample at 1-pixel intervals about the centre of the line using nearest-neighbour interpolation.
PIXELSTEP_NEAREST_NEIGHBOUR_DERIVATIVE Sample at 1-pixel intervals about the centre of the line using nearest neighbour interpolation to estimate values and then compute the derivative using [1 0 -1] filter.

Method Summary

Modifier and Type	Method and Description
abstract float[]	extractSamples(Line2d line, FImage image, int numSamples) Extract a numSamples samples along the given line in the given image.
Line2d	getSampleLine(Line2d line, FImage image, int numSamples) Get the a line representing the extremities of the pixels that are actually sampled.
static FLineSampler	valueOf(String name) Returns the enum constant of this type with the specified name.
static FLineSampler[]	values() Returns an array containing the constants of this enum type, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Detail

PIXELSTEP_NEAREST_NEIGHBOUR

public static final FLineSampler PIXELSTEP_NEAREST_NEIGHBOUR

Sample at 1-pixel intervals about the centre of the line using nearest-neighbour interpolation. The overall length of the line is ignored. Values outside the image are considered to be 0.

NEAREST_NEIGHBOUR

public static final FLineSampler NEAREST_NEIGHBOUR

Sample the pixel values at regular intervals along the full length of the line taking the sample value from the nearest pixel. Pixels outside the image have a value of 0.

PIXELSTEP_INTERPOLATED

public static final FLineSampler PIXELSTEP_INTERPOLATED

Sample at 1-pixel intervals about the centre of the line using bilinear interpolation to estimate sub-pixel values. The overall length of the line is ignored. Values outside the image are considered to be 0.

INTERPOLATED

public static final FLineSampler INTERPOLATED

Sample the pixel values at regular intervals along the full length of the line using bilinear interpolation to get sub-pixel values.

PIXELSTEP_NEAREST_NEIGHBOUR_DERIVATIVE

public static final FLineSampler PIXELSTEP_NEAREST_NEIGHBOUR_DERIVATIVE

Sample at 1-pixel intervals about the centre of the line using nearest neighbour interpolation to estimate values and then compute the derivative using [1 0 -1] filter. The number of regular samples is two bigger than the requested number so the number of derivative samples is as requested. The overall length of the line is ignored. Values outside the image are considered to be 0.

NEAREST_NEIGHBOUR_DERIVATIVE

public static final FLineSampler NEAREST_NEIGHBOUR_DERIVATIVE

Sample the pixel values at regular intervals along the full length of the line using nearest-neighbour pixels and then compute the derivative using [1 0 -1] filter. The number of regular samples is two bigger than the requested number so the number of derivative samples is as requested.

PIXELSTEP_INTERPOLATED_DERIVATIVE

public static final FLineSampler PIXELSTEP_INTERPOLATED_DERIVATIVE

Sample at 1-pixel intervals about the centre of the line using bilinear interpolation to estimate sub-pixel values and then compute the derivative using [1 0 -1] filter. The number of regular samples is two bigger than the requested number so the number of derivative samples is as requested. The overall length of the line is ignored. Values outside the image are considered to be 0.

INTERPOLATED_DERIVATIVE

public static final FLineSampler INTERPOLATED_DERIVATIVE

Sample the pixel values at regular intervals along the full length of the line using bilinear interpolation and then compute the derivative using [1 0 -1] filter. The number of regular samples is two bigger than the requested number so the number of derivative samples is as requested.

Method Detail

values

public static FLineSampler[] values()

Returns an array containing the constants of this enum type, in the order they are declared. This method may be used to iterate over the constants as follows:

for (FLineSampler c : FLineSampler.values())
    System.out.println(c);

Returns:

an array containing the constants of this enum type, in the order they are declared

valueOf

public static FLineSampler valueOf(String name)

Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum type has no constant with the specified name

NullPointerException - if the argument is null

getSampleLine

public Line2d getSampleLine(Line2d line,
                            FImage image,
                            int numSamples)

Description copied from interface: LineSampler

Get the a line representing the extremities of the pixels that are actually sampled.

Specified by:

getSampleLine in interface LineSampler<FImage,float[]>

Parameters:

line - the line

image - the image to sample from

numSamples - the number of samples

Returns:

the sampling line

extractSamples

public abstract float[] extractSamples(Line2d line,
                                       FImage image,
                                       int numSamples)

Description copied from interface: LineSampler

Extract a numSamples samples along the given line in the given image. Implementors may choose to interpret the line in different ways; some may sample numSamples between the start and end points, whilst others may choose different sampling points along the direction of the line.

Specified by:

extractSamples in interface LineSampler<FImage,float[]>

Parameters:

line - the line

image - the image to sample from

numSamples - the number of samples

Returns:

the samples