Stitch multiple giottoLargeImage objects into a single giottoLargeImage object#

Last Updated: Sep 07, 2023

Description#

Function to stitch together multiple field of view (FOV) images into a single final image. Images are loaded into Giotto as giottoLargeImage and stitched based on a set of FOV positions into a single final giottoLargeImage.

Usage#

stitchGiottoLargeImage(
  largeImage_list = NULL,
  gobject_list = NULL,
  largeImage_nameList = NULL,
  FOV_positions = NULL,
  FOV_xcol = NULL,
  FOV_ycol = NULL,
  FOV_inverty = FALSE,
  method = c("mosaic", "merge"),
  round_positions = FALSE,
  filename = NULL,
  dataType = NULL,
  fileType = NULL,
  dryRun = TRUE,
  overwrite = FALSE,
  verbose = TRUE
)

Arguments#

`largeImage_list`	list of `giottoLargeImage` objects
`gobject_list`	list of `gobjects` containing `giottoLargeImages`
`largeImage_nameList`	list of names of `giottoLargeImages` within `gobjects`
`FOV_positions`	dataframe of FOV positions. Values (if any) are directly added to current image mapping
`FOV_xcol`	column name for FOV position x values
`FOV_ycol`	column name for FOV position y values
`FOV_inverty`	make FOV y position values negative
`method`	method of stitching images (mosaic: average overlapping area values, merge:values get priority by order of images given)
`round_positions`	[boolean] round image positions. May be necessary to run.
`filename`	file name to write the stitched image to. Defaults to `"save_dir/stitch.tif"` if `save_dir` param is found in the first `gobject`’s Giotto instructions
`dataType`	(optional) values for `dataType` are “INT1U”, “INT2U”, “INT2S”, “INT4U”, “INT4S”, “FLT4S”, “FLT8S”. The first three letters indicate whether the `dataType` is integer (whole numbers) of a real number (decimal numbers), the fourth character indicates the number of bytes used (allowing for large numbers and/or more precision), and the “S” or “U” indicate whether the values are signed (both negative and positive) or unsigned (positive values only).
`fileType`	(optional) image format (e.g. .tif) If not given, defaults to format given in the filename
`dryRun`	[boolean] plot placeholder bounding rectangles where FOV images will be stitched without actually proceeding with the full image stitching and saving process.
`overwrite`	[boolean] overwrite if filename to save image as already exists. Defaults to TRUE
`verbose`	[boolean] be verbose

Details#

This function is time consuming. Setting a save location through the filename parameter is also highly recommended as file size will likely be large. This function creates a single stitched image from multiple FOV tiles and saves that image to disk as it works. When finished, the pointer to that new image is loaded in as a giottoLargeImage object.

Note: Dry runs are on by default and dryRun param must be set to FALSE to proceed with the final stitching operation.

Value#

largeGiottoImage object with pointer to stitched image

Dry runs are default#

To ensure that disk space and time is not wasted, this function defaults to previewing the stitching operation.

FOV positions#

The final image is stitched together from multiple FOV tiles. The FOV_positions parameter accepts a table of x and y values for where each FOV tile should be placed when performing the stitch. Which columns are the x and y values are determined by the FOV_xcol and FOV_ycol params respectively. FOV tiles are at full resolution with a starting position where either the lower left or upper left of the image touch the origin depending on the value of FOV_inverty param. The FOV image is then translated according to the x and y shift values.

FOV invert y#

Many imaging systems may treat the origin according to image convention where (0,0) is at the upper left of an image. This is at odds with coordinate convention and what Giotto uses internally where the coordinate (0,0) is at the lower left. The FOV_inverty defaults to FALSE, but if set to TRUE, then FOV tile images will start with the upper left touching (0,0) and all y values given through FOV_positions and FOV_ycol will be treated as negative y shift values.

dataType#

There are multiple datatypes defining the range of intensity values that images can be saved with. Setting a value with the dataType para is optional and Giotto attempts to determine compatible data type to save the image as automatically.