writeall
Description
writeall(
writes the data from the blocked image datastore bimds
,outputLocation
)bimds
to PNG files at
the location specified in outputLocation
. The number of output files is
the same as the number of files referenced by the datastore.
writeall(
writes data with additional options specified by one or more name-value arguments. For
example, you can specify bimds
,outputLocation
,Name=Value
)OutputFormat
and a file extension such as
"png"
to specify the type of files that writeall
creates.
Examples
Write All Blocks as PNG Files
Create a blocked image.
bim = blockedImage("tumor_091R.tif");
Create a datastore, specifying the resolution level and the block size.
bls = selectBlockLocations(bim,Levels=2,BlockSize=[512, 512]); bimds = blockedImageDatastore(bim,BlockLocationSet=bls);
Write all blocks of the datastore as PNG files in a subdirectory of the current directory.
dir = "tumor_091R_PNG_"+string(datetime("now",Format="yyyy-MM-dd-HH-mm-ss")); writeall(bimds,dir)
Write All Blocks as TIFF Files
Create a blocked image datastore.
bim = blockedImage("tumor_091R.tif");
bls = selectBlockLocations(bim,Levels=2,BlockSize=[512, 512]);
bimds = blockedImageDatastore(bim,BlockLocationSet=bls);
Write all blocks of the datastore as TIFF files in a subdirectory of the current directory, and add a suffix with the current time to each filename.
dir = "tumor_091R_TIFF"; writeall(bimds,dir,OutputFormat="TIFF",WriteFcn=@myTIFFWriteFcn, ... FilenameSuffix="__"+string(datetime("now",Format="yyyy-MM-dd-HH-mm-ss")))
The custom write function myTIFFWriteFcn
writes blocks of data as TIFF files.
function myTIFFWriteFcn(data,writeInfo,outputType) if strcmp(outputType,"TIFF") dir = writeInfo.Location; filename = writeInfo.SuggestedOutputName; imwrite(data,dir+filesep+filename,"tiff") end end
Input Arguments
bimds
— Blocked image datastore
blockedImageDatastore
object
Blocked image datastore, specified as a blockedImageDatastore
object.
outputLocation
— Folder location to write data
character vector | string scalar
Folder location to write data, specified as a character vector or string scalar.
outputLocation
can specify a full or relative path.
Example: outputLocation = "../../dir/data"
Example: outputLocation = "C:\Users\MyName\Desktop"
Data Types: char
| string
Name-Value Arguments
Specify optional pairs of arguments as
Name1=Value1,...,NameN=ValueN
, where Name
is
the argument name and Value
is the corresponding value.
Name-value arguments must appear after other arguments, but the order of the
pairs does not matter.
Example: writeall(bimds,outputLocation,OutputFormat="jpeg")
writes the
files from the datastore bimds
to the output location in the JPEG
format.
OutputFormat
— Output file format
"png"
(default) | "jpeg"
| "jpg"
| "mat"
| character vector | string scalar
Output file format, specified as "jpeg"
,
"jpg"
, "png"
, "mat"
, or a
string scalar or character vector. For the "jpeg"
and
"jpg"
output formats, you can refine the writing operation using
the Quality
name-value argument.
If you need to write files of a different format than JPEG, JPG, PNG, or MAT, then
use both the OutputFormat
and WriteFcn
arguments.
Data Types: char
| string
FilenamePrefix
— Prefix to filename
[]
(default) | character vector | string scalar
Prefix to filename, specified as a character vector or string scalar.
The writeall
function adds the specified prefix to each
output filename. For example, this code adds the current date to the beginning of all
filenames output from the
datastore:
prefixText = string(datetime("today")) writeall(bimds,"C:\myFolder",FilenamePrefix=prefixText)
Data Types: char
| string
FilenameSuffix
— Suffix to filename
[]
(default) | character vector | string scalar
Suffix to filename, specified as a character vector or string scalar.
The writeall
function adds the specified suffix to each
output filename. For example, this code adds the descriptive text
"jpeg_qual70"
to the end of all filenames output from the
datastore:
writeall(bimds,"C:\myFolder",FilenameSuffix="jpeg_qual70")
Data Types: char
| string
UseParallel
— Write in parallel
false
or 0
(default) | true
or 1
Write blocks in parallel, specified as a numeric or
logical 0
(false
) or 1
(true
). By default, writeall
writes in serial. If you set
UseParallel
to true
, then
writeall
divides the writing operations into separate groups
and runs the groups in parallel if:
Parallel Computing Toolbox™ is installed.
An open parallel pool exists or automatic pool creation is enabled in the Parallel Preferences.
Otherwise, writeall
writes in serial regardless of the value
for UseParallel
. The writeall
function does not
support writing in parallel via local threads.
Data Types: logical
WriteFcn
— Custom writing function
function handle
Custom writing function, specified as a function handle.
writeall
uses the specified function to create the output
files.
You can use the WriteFcn
argument to write data in a variety
of formats, even if writeall
does not directly support the output
format.
Functional Signature
The custom writing function must accept at least three input arguments,
data
, writeInfo
, and
outputType
:
function myWriteFcn(data,writeInfo,outputType)
data
contains the output of theread
function operating on the datastore.writeInfo
is an object of typematlab.io.datastore.WriteInfo
with the fields listed in this table.Field Description Type ReadInfo
The second output of the read
functionstruct
SuggestedOutputName
A fully qualified, globally unique filename that meets the location and naming requirements string
Location
The outputLocation
argument passed to thewriteall
functionstring
outputType
is the output format to be written to, such as"jpg"
or"png"
.
Example Function
This function writes TIFF files from a blocked image datastore:
function myTIFFWriteFcn(data,writeInfo,outputType) if strcmp(outputType,"tiff") dir = writeInfo.Location; filename = writeInfo.SuggestedOutputName; imwrite(data,dir+filesep+filename,"tiff") end end
myTIFFWriteFcn
as the writing function for datastore
bimds
, use these
commands:outputLocation = "C:/MyData";
writeall(bimds,outputLocation,WriteFcn=@myTIFFWriteFcn)
Data Types: function_handle
jpeg
or jpg
OutputQuality
— Quality of JPEG-compressed file
75
(default) | number in range [0, 100]
Quality of the JPEG-compressed file, specified as a number in the range [0, 100], where 0 is lower quality and higher compression, and 100 is higher quality and lower compression.
Tips
The default output filename has the form
Image_<N>_Level_<L>_Block_<blockOrigin>.<ext>
. For example,Image_1_Level_1_Block_1_1_1.jpg
. The function pads the values of<N>
and<L>
with leading 0s, if required.
Version History
Introduced in R2023a
See Also
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