def_features: Define features

In OpenSpecy: Analyze, Process, Identify, and Share Raman and (FT)IR Spectra

Define features

Description

Functions for analyzing features, like particles, fragments, or fibers, in spectral map oriented OpenSpecy object.

Usage

collapse_spec(x, ...)

## Default S3 method:
collapse_spec(x, ...)

## S3 method for class 'OpenSpecy'
collapse_spec(x, fun = median, column = "feature_id", ...)

def_features(x, ...)

## Default S3 method:
def_features(x, ...)

## S3 method for class 'OpenSpecy'
def_features(
  x,
  features,
  shape_kernel = c(3, 3),
  shape_type = "box",
  close = F,
  close_kernel = c(4, 4),
  close_type = "box",
  img = NULL,
  bottom_left = NULL,
  top_right = NULL,
  ...
)

Arguments

x	an OpenSpecy object
fun	function name to collapse by.
column	column name in metadata to collapse by.
features	a logical vector or character vector describing which of the spectra are of features (TRUE) and which are not (FALSE). If a character vector is provided, it should represent the different feature types present in the spectra.
shape_kernel	the width and height of the area in pixels to search for connecting features, c(3,3) is typically used but larger numbers will smooth connections between particles more.
shape_type	character, options are for the shape used to find connections c("box", "disc", "diamond")
close	logical, whether a closing should be performed using the shape kernel before estimating components.
close_kernel	width and height of the area to close if using the close option.
close_type	character, options are for the shape used to find connections c("box", "disc", "diamond")
img	a file location where a visual image is that corresponds to the spectral image.
bottom_left	a two value vector specifying the x,y location in image pixels where the bottom left of the spectral map begins. y values are from the top down while x values are left to right.
top_right	a two value vector specifying the x,y location in the visual image pixels where the top right of the spectral map extent is. y values are from the top down while x values are left to right.
...	additional arguments passed to subfunctions.

Details

def_features() accepts an OpenSpecy object and a logical or character vector describing which pixels correspond to particles. collapse_spec() takes an OpenSpecy object with particle-specific metadata (from def_features()) and collapses the spectra with a function intensities for each unique particle. It also updates the metadata with centroid coordinates, while preserving the feature information on area and Feret max.

Value

An OpenSpecy object appended with metadata about the features or collapsed for the features. All units are in pixels. Metadata described below.

x

x coordinate of the pixel or centroid if collapsed

y

y coordinate of the pixel or centroid if collapsed

feature_id

unique identifier of each feature

area

area in pixels of the feature

perimeter

perimeter of the convex hull of the feature

feret_min

feret_max divided by the area

feret_max

largest dimension of the convex hull of the feature

convex_hull_area

area of the convex hull

centroid_x

mean x coordinate of the feature

centroid_y

mean y coordinate of the feature

first_x

first x coordinate of the feature

first_y

first y coordinate of the feature

rand_x

random x coordinate from the feature

rand_y

random y coordinate from the feature

r

if using visual imagery overlay, the red band value at that location

g

if using visual imagery overlay, the green band value at that location

b

if using visual imagery overlay, the blue band value at that location

Author(s)

Win Cowger, Zacharias Steinmetz

Examples

tiny_map <- read_extdata("CA_tiny_map.zip") |> read_any()
identified_map <- def_features(tiny_map, tiny_map$metadata$x == 0)
collapse_spec(identified_map)

OpenSpecy documentation built on Sept. 14, 2024, 9:07 a.m.