imwrite
Write image to graphics file
Description
imwrite(
writes
image data A
,filename
)A
to the file specified by filename
,
inferring the file format from the extension. imwrite
creates
the new file in your current folder. The bit depth of the output image
depends on the data type of A
and the file format.
For most formats:
If
A
is of data typeuint8
, thenimwrite
outputs 8-bit values.If
A
is of data typeuint16
and the output file format supports 16-bit data (JPEG, PNG, and TIFF), thenimwrite
outputs 16-bit values. If the output file format does not support 16-bit data, thenimwrite
returns an error.If
A
is a grayscale or RGB color image of data typedouble
orsingle
, thenimwrite
assumes that the dynamic range is [0,1] and automatically scales the data by 255 before writing it to the file as 8-bit values. If the data inA
issingle
, convertA
todouble
before writing to a GIF or TIFF file.If
A
is of data typelogical
, thenimwrite
assumes that the data is a binary image and writes it to the file with a bit depth of 1, if the format allows it. BMP, PNG, or TIFF formats accept binary images as input arrays.
If A
contains indexed image data, you should
additionally specify the map
input argument.
imwrite(
writes
the indexed image in A
,map
,filename
)A
and its associated colormap, map
,
to the file specified by filename
.
If
A
is an indexed image of data typedouble
orsingle
, thenimwrite
converts the indices to zero-based indices by subtracting 1 from each element, and then writes the data asuint8
. If the data inA
issingle
, convertA
todouble
before writing to a GIF or TIFF file.
imwrite(___,
writes
the image in the format specified by fmt
)fmt
, regardless
of the file extension in filename
. You can specify fmt
after
the input arguments in any of the previous syntaxes.
imwrite(___,
specifies
additional parameters for output GIF, HDF, JPEG, PBM, PGM, PNG, PPM,
and TIFF files, using one or more name-value pair arguments. You can
specify Name,Value
)Name,Value
after the input arguments in
any of the previous syntaxes.
Examples
Write Grayscale Image to PNG
Write a 50-by-50 array of grayscale values to a PNG file in the current folder.
A = rand(50);
imwrite(A,'myGray.png')
Write Indexed Image Data to PNG
Write an indexed image array and its associated colormap to a PNG file.
Load sample image data from the file, clown.mat
.
load clown.mat
The image array X
and its associated colormap, map
,
are loaded into the MATLAB® workspace.
Write the data to a new PNG file.
imwrite(X,map,'myclown.png')
imwrite
creates the file, myclown.png
,
in your current folder.
View the new file by opening it outside of MATLAB.
Write Indexed Image with MATLAB Colormap
Write image data to a new PNG file with the
built-in MATLAB colormap, copper
.
Load sample image data from the file clown.mat
.
load clown.mat
The image array X
and its associated colormap, map
,
are loaded into the MATLAB workspace. map
is
a matrix of 81 RGB vectors.
Define a copper-tone colormap with 81 RGB vectors. Then, write the image data to a PNG file using the new colormap.
newmap = copper(81);
imwrite(X,newmap,'copperclown.png');
imwrite
creates the file, copperclown.png
,
in your current folder.
View the new file by opening it outside of MATLAB.
Write Truecolor Image to JPEG
Create and write truecolor image data to a JPEG file.
Create a 49-by-49-by-3 array of random RGB values.
A = rand(49,49); A(:,:,2) = rand(49,49); A(:,:,3) = rand(49,49);
Write the image data to a JPEG file, specifying the output
format using 'jpg'
. Add a comment to the file using
the 'Comment'
name-value pair argument.
imwrite(A,'newImage.jpg','jpg','Comment','My JPEG file')
View information about the new file.
imfinfo('newImage.jpg')
ans = Filename: 'S:\newImage.jpg' FileModDate: '25-Jan-2013 16:18:41' FileSize: 2339 Format: 'jpg' FormatVersion: '' Width: 49 Height: 49 BitDepth: 24 ColorType: 'truecolor' FormatSignature: '' NumberOfSamples: 3 CodingMethod: 'Huffman' CodingProcess: 'Sequential' Comment: {'My JPEG file'}
Write Multiple Images to TIFF File
Write multiple images to a single multipage TIFF file.
Create two sets of random image data, im1
and im2
.
im1 = rand(50,40,3); im2 = rand(50,50,3);
Write the first image to a new TIFF file. Then, append the second image to the same file.
imwrite(im1,'myMultipageFile.tif') imwrite(im2,'myMultipageFile.tif','WriteMode','append')
Write Animated GIF
Draw a series of plots, capture them as images, and write them into one animated GIF file.
Plot for
.
x = 0:0.01:1; n = 3; y = x.^n; plot(x,y,'LineWidth',3) title(['y = x^n, n = ' num2str(n) ])
Capture a series of plots for increasing values of .
n = 1:0.5:5; nImages = length(n); fig = figure; for idx = 1:nImages y = x.^n(idx); plot(x,y,'LineWidth',3) title(['y = x^n, n = ' num2str( n(idx)) ]) drawnow frame = getframe(fig); im{idx} = frame2im(frame); end close;
Display the series of images in one figure.
figure; for idx = 1:nImages subplot(3,3,idx) imshow(im{idx}); end
Save the nine images into a GIF file. Because three-dimensional data is not supported for GIF files, call rgb2ind
to convert the RGB data in the image to an indexed image A
with a colormap map
. To append multiple images to the first image, call imwrite
with the name-value pair argument 'WriteMode','append'
.
filename = 'testAnimated.gif'; % Specify the output file name for idx = 1:nImages [A,map] = rgb2ind(im{idx},256); if idx == 1 imwrite(A,map,filename,'gif','LoopCount',Inf,'DelayTime',1); else imwrite(A,map,filename,'gif','WriteMode','append','DelayTime',1); end end
imwrite
writes the GIF file to your current folder. Name-value pair 'LoopCount',Inf
causes the animation to continuously loop. 'DelayTime',1
specifies a 1-second delay between the display of each image in the animation.
Input Arguments
A
— Image data
matrix
Image data, specified as a full (nonsparse) matrix.
For grayscale images,
A
can bem
-by-n
.For indexed images,
A
can bem
-by-n
. Specify the associated colormap in themap
input argument.For truecolor images,
A
must bem
-by-n
-by-3.imwrite
does not support writing RGB images to GIF files.
For TIFF files, A
can be an
m
-by-n
-by-4 array containing color data that
uses the CMYK color space.
For multiframe GIF files, A
can be an
m
-by-n
-by-1-by-p
array
containing grayscale or indexed images, where p
is the number of
frames to write. RGB images are not supported in this case.
Data Types: double
| single
| uint8
| uint16
| logical
filename
— Name of output file
character vector | string scalar
Name of the output file, specified as a character vector or string scalar.
Depending on the location you are writing to, filename
can take
on one of these forms.
Location | Form | ||||||||
---|---|---|---|---|---|---|---|---|---|
Current folder | To write to the current folder, specify the name of the file in
Example:
| ||||||||
Other folders | To write to a folder different from the current folder, specify the
full or relative path name in
Example:
Example:
| ||||||||
Remote Location | To write to a remote location,
Based on the remote location,
For more information, see Work with Remote Data. Example:
|
Data Types: char
| string
map
— Colormap of indexed image
m
-by-3 array
Colormap associated with indexed image data in A
,
specified as an m
-by-3 array. map
must
be a valid MATLAB colormap. See colormap
for
a list of built-in MATLAB colormaps. Most image file formats
do not support colormaps with more than 256 entries.
Example: [0,0,0;0.5,0.5,0.5;1,1,1]
Example: jet(60)
Data Types: double
fmt
— Format of output file
'bmp'
| 'gif'
| 'hdf'
| 'jpg'
| 'jp2'
| ...
Format of the output file, specified as one of the formats in this table.
This table also summarizes the types of images
that imwrite
can write. The MATLAB file
format registry determines which file formats are supported. See imformats
for more information about
this registry.
For certain formats, imwrite
can accept
additional name-value pair arguments. To view these arguments, click
the linked format names below.
Value of | Format of Output File | Description |
---|---|---|
| Windows® Bitmap (BMP) | 1-bit, 8-bit, and 24-bit uncompressed images |
| 8-bit images | |
| 8-bit raster image data sets with or without associated colormap, 24-bit raster image data sets | |
| 8-bit, 12-bit, and 16-bit Baseline JPEG images Note
| |
| 1-bit, 8-bit, and 16-bit JPEG 2000 images | |
| Any 1-bit PBM image, ASCII (plain) or raw (binary) encoding | |
| Windows Paintbrush (PCX) | 8-bit images |
| Any standard PGM image; ASCII (plain) encoded with arbitrary color depth; raw (binary) encoded with up to 16 bits per gray value | |
| 1-bit, 2-bit, 4-bit, 8-bit, and 16-bit grayscale images; 8-bit and 16-bit grayscale images with alpha channels; 1-bit, 2-bit, 4-bit, and 8-bit indexed images; 24-bit and 48-bit truecolor images; 24-bit and 48-bit truecolor images with alpha channels
Note The
| |
| Any of the PPM/PGM/PBM formats, chosen automatically | |
| Any standard PPM image: ASCII (plain) encoded with arbitrary color depth or raw (binary) encoded with up to 16 bits per color component | |
| Sun™ Raster (RAS) | Any RAS image, including 1-bit bitmap, 8-bit indexed, 24-bit truecolor, and 32-bit truecolor with alpha |
| Baseline TIFF images, including:
| |
| X Windows Dump (XWD) | 8-bit ZPixmaps |
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.
Before R2021a, use commas to separate each name and value, and enclose
Name
in quotes.
Example: imwrite(A,'myFile.png','BitDepth',8)
writes the data in
A
using 8 bits to represent each pixel.
BackgroundColor
— Color to use as background color
scalar integer
Color to use as background color for the indexed image, specified as the
comma-separated pair consisting of 'BackgroundColor'
and a scalar
integer corresponding to the colormap index.
The background color is used for some disposal methods in animated GIFs.
If image data
A
isuint8
orlogical
, then the colormap index is zero-based.If image data
A
isdouble
, then the colormap index is one-based.
The default background color corresponds to the first color in the colormap.
Example: 'BackgroundColor',15
Comment
— Comment to add to image
character vector | string scalar | cell array of character vectors | string array
Comment to add to the image, specified as the comma-separated pair consisting of
'Comment'
and a character vector, string scalar, a
1-by-n
cell array of character vectors, or a string array. For a
cell array of character vectors, imwrite
adds a carriage return
after each character vector.
Example: 'Comment',{'Sample #314','January 5,
2013'}
Data Types: char
| cell
| string
DelayTime
— Delay before displaying next image
0.5 (default) | scalar value in the range [0,655]
Delay before displaying next image, in seconds, specified as the comma-separated
pair consisting of 'DelayTime'
and a scalar value in the range
[0,655]. A value of 0
displays images as fast as your hardware
allows.
Example: 'DelayTime',60
DisposalMethod
— Disposal method of animated GIF
'doNotSpecify'
(default) | 'leaveInPlace'
| 'restoreBG'
| 'restorePrevious'
Disposal method of an animated GIF, specified as the comma-separated pair
consisting of 'DisposalMethod'
and one of the methods in this
table.
Value of DisposalMethod
| Result |
---|---|
'doNotSpecify' (default) | Replace one full-size, nontransparent frame with another. |
'leaveInPlace' | Any pixels not covered up by the next frame continue to display. |
'restoreBG' | The background color or background tile shows through transparent pixels. |
'restorePrevious' | Restore to the state of a previous, undisposed frame. |
Example: 'DisposalMethod','restoreBG'
Location
— Offset of screen relative to image
[0,0]
(default) | two-element vector
Offset of the screen relative to the image, measured from the top left corner of
each, specified as the comma-separated pair consisting of
'Location'
and a two-element vector. The first vector element
specifies the offset from the top, and the second element specifies the offset from
the left, in pixels.
Example: 'Location',[10,15]
Data Types: double
LoopCount
— Number of times to repeat animation
Inf
(default) | integer in the range [0,65535]
Number of times to repeat the animation, specified as the comma-separated pair
consisting of 'LoopCount'
and either an integer in the range
[0,65535]
, or the value Inf
. If you specify 0,
the animation plays once. If you specify the value 1, the animation plays twice, and
so on. A LoopCount
value of Inf
causes the
animation to continuously loop.
To enable animation within Microsoft®
PowerPoint®, specify a value for 'LoopCount'
within the range
[1,65535]. Some Microsoft applications interpret the value 0 to mean do not loop at all.
Example: 'LoopCount',3
ScreenSize
— Height and width of frame
height and width of input image (default) | two-element vector
Height and width of the frame, specified as the comma-separated pair consisting of
'ScreenSize'
and a two-element vector. When you use the
ScreenSize
argument with 'Location'
, it
provides a way to write frames to the image that are smaller than the whole frame.
'DisposalMethod'
determines the fill value for pixels outside the
frame.
Example: 'ScreenSize',[1000 1060]
Data Types: double
TransparentColor
— Color to use as transparent color
scalar integer
Color to use as transparent color for the image, specified as the comma-separated
pair consisting of 'TransparentColor'
and a scalar integer
corresponding to the colormap index.
If image data
A
isuint8
orlogical
, then indexing begins at0
.If image data
A
isdouble
, then indexing begins at1
.
Example: 'TransparentColor',20
WriteMode
— Writing mode
'overwrite'
(default) | 'append'
Writing mode, specified as the comma-separated pair consisting of
'WriteMode'
and either 'overwrite'
or
'append'
. In overwrite
mode,
imwrite
overwrites an existing
file,filename
. In append
mode,
imwrite
adds a single frame to the existing file.
Example: 'WriteMode','append'
Compression
— Compression scheme
'none'
(default) | 'jpeg'
| 'rle'
Compression scheme, specified as the comma-separated pair consisting of
'Compression'
and one of the options in this table.
Value of Compression
| Result |
---|---|
'none' (default) | No compression |
'jpeg' | JPEG compression. Valid only for grayscale and RGB images. |
'rle' | Run-length encoding. Valid only for grayscale and indexed images. |
Example: 'Compression','jpeg'
Quality
— Quality of JPEG-compressed file
75 (default) | scalar in the range [0,100]
Quality of the JPEG-compressed file, specified as the comma-separated pair
consisting of 'Quality'
and a scalar in the range [0,100], where 0
is lower quality and higher compression, and 100 is higher quality and lower
compression. This parameter applies only if 'Compression'
is
'jpeg'
.
Example: 'Quality',25
WriteMode
— Writing mode
'overwrite'
(default) | 'append'
Writing mode, specified as the comma-separated pair consisting of
'WriteMode'
and either 'overwrite'
or
'append'
. In overwrite
mode,
imwrite
overwrites an existing
file,filename
. In append
mode,
imwrite
adds a single frame to the existing file.
Example: 'WriteMode','append'
BitDepth
— Number of bits per pixel
8 (default) | scalar
Number of bits per pixel, specified as the comma-separated pair consisting of
'BitDepth'
and a scalar.
For grayscale images, the
BitDepth
value can be 8, 12, or 16. The default value is 8. For 16-bit images, the'Mode'
name-value pair argument must be'lossless'
.For color images, the
BitDepth
value is the number of bits per plane, and can be 8 or 12. The default is 8 bits per plane.
Example: 'BitDepth',12
Comment
— Comment to add to image
character vector | character array | n
-by-1 cell array of character vectors
Comment to add to the image, specified as the comma-separated pair consisting of
'Comment'
and a character vector, a string scalar, a character
array, an n
-by-1 cell array of character vectors, or a string
array. imwrite
writes each row of input as a comment in the JPEG
file.
Example: 'Comment',{'First line';'second line';'third
line'}
Data Types: char
| string
| cell
Mode
— Type of compression
'lossy'
(default) | 'lossless'
Type of compression, specified as the comma-separated pair consisting of
'Mode'
and one of these options:
'lossy'
'lossless'
Example: 'Mode','lossless'
Quality
— Quality of output file
75 (default) | scalar in the range [0,100]
Quality of the output file, specified as the comma-separated pair consisting of
'Quality'
and a scalar in the range [0,100], where 0 is lower
quality and higher compression, and 100 is higher quality and lower compression. A
Quality
value of 100 does not write a lossless JPEG image.
Instead, use the 'Mode','lossless'
name-value pair argument.
Example: 'Quality',100
Comment
— Comment to add to image
character vector | string scalar | character array | n
-by-1 cell array of character vectors | string array
Comment to add to the image, specified as the comma-separated pair consisting of
'Comment'
and a character vector, a character array, string
scalar, a cell array of character vectors, or string array.
imwrite
writes each row of input as a comment in the JPEG 2000
file.
Example: 'Comment',{'First line';'second line';'third
line'}
Example: 'Comment',{'First line','second line','third
line'}
Data Types: cell
| char
| string
CompressionRatio
— Target compression ratio
1 (default) | scalar
Target compression ratio, specified as the comma-separated pair consisting of
'CompressionRatio'
and a real scalar greater than or equal to 1.
The compression ratio is the ratio of the input image size to the output compressed
size. For example, a value of 2.0 implies that the output image size is half of the
input image size or less. A higher value implies a smaller file size and reduced image
quality. The compression ratio does not take into account the header size.
Specifying CompressionRatio
is valid only when
'Mode'
is 'lossy'
.
Example: 'CompressionRatio',3
Mode
— Type of compression
'lossy'
(default) | 'lossless'
Type of compression, specified as the comma-separated pair consisting of
'Mode'
and one of these options:
'lossy'
'lossless'
Example: 'Mode','lossless'
ProgressionOrder
— Order of packets in code stream
'LRCP'
(default) | 'RLCP'
| 'RPCL'
| 'PCRL'
| 'CPRL'
Order of packets in the code stream, specified as the comma-separated pair
consisting of 'ProgressionOrder'
and one of these options:
'LRCP'
'RLCP'
'RPCL'
'PCRL'
'CPRL'
The characters represent the following: L
= layer,
R
= resolution, C
= component and
P
= position.
Example: 'ProgressionOrder','RLCP'
QualityLayers
— Number of quality layers
1 (default) | integer in the range [1,20]
Number of quality layers, specified as the comma-separated pair consisting of
'QualityLayers'
and an integer in the range [1,20].
Example: 'QualityLayers',8
ReductionLevels
— Number of reduction levels
4 (default) | integer in the range [1,8]
Number of reduction levels, or wavelet decomposition levels, specified as the
comma-separated pair consisting of 'ReductionLevels'
and an integer
in the range [1,8].
Example: 'ReductionLevels',6
TileSize
— Tile height and width
image size (default) | two-element vector
Tile height and width, specified as the comma-separated pair consisting of
'TileSize'
and a two-element vector. The minimum size you can
specify is [128 128]
.
Example: 'TileSize',[130 130]
Encoding
— Encoding
'rawbits'
(default) | 'ASCII'
Encoding, specified as the comma-separated pair consisting of
'Encoding'
and either 'rawbits'
for binary
encoding, or 'ASCII'
for plain encoding.
Example: 'Encoding','ASCII'
MaxValue
— Maximum gray or color value
scalar
Maximum gray or color value, specified as the comma-separated pair consisting of
'MaxValue'
and a scalar.
Available only for PGM and PPM files. For PBM files, this value is always 1.
If the image array is uint16
, then the default value for
MaxValue
is 65535
. Otherwise, the default
value is 255
.
Example: 'MaxValue',510
Alpha
— Transparency of each pixel
matrix of values in the range [0,1]
Transparency of each pixel, specified as the comma-separated pair consisting of
'Alpha'
and a matrix of values in the range [0,1]. The row and
column dimensions of the Alpha
matrix must be the same as those of
the image data array. You can specify Alpha
only for grayscale
(m
-by-n
) and truecolor
(m
-by-n
-by-3) image data.
Note
You cannot specify both 'Alpha'
and
'Transparency'
at the same time.
Data Types: double
| uint8
| uint16
Author
— Author information
character vector | string scalar
Author information, specified as the comma-separated pair consisting of
'Author'
and a character vector or string scalar.
Example: "Author','Ann Smith'
Data Types: char
Background
— Background color when compositing transparent pixels
scalar in the range [0,1]
| integer in the range [1,P]
| 3-element vector in the range [0,1]
Background color when compositing transparent pixels, specified as the
comma-separated pair consisting of 'Background'
and a value
dependent on the image data, as follows.
Image Type | Form of Background Value |
---|---|
Grayscale images | Scalar in the range [0,1] . |
Indexed images | Integer in the range [1,P] , where P
is the colormap length. For example, 'Background',50 sets
the background color to the color specified by the 50th index in the
colormap. |
Truecolor images | Three-element vector of RGB intensities in the range
[0,1] . For example, 'Background',[0 1
1] sets the background color to cyan. |
Data Types: double
BitDepth
— Number of bits per pixel
scalar
Number of bits per pixel, specified as the comma-separated pair consisting of
'BitDepth'
and a scalar. Depending on the output image, the
scalar can be one of the following values.
Image Type | Allowed Values for BitDepth |
---|---|
Grayscale images | 1 , 2 , 4 ,
8 , or 16 |
Grayscale images with an alpha channel | 8 or 16 |
Indexed images | 1 , 2 , 4 , or
8 |
Truecolor images | 8 or 16 |
If the image is of class
double
oruint8
, then the default bit depth is 8 bits per pixel.If the image is
uint16
, then the default is 16 bits per pixel.If the image is
logical
, then the default is 1 bit per pixel.
Example: 'BitDepth',4
Chromaticities
— Reference white point and primary chromaticities
8-element vector
Reference white point and primary chromaticities, specified as the comma-separated
pair consisting of 'Chromaticities'
and an 8-element vector,
[wx wy rx ry gx gy bx by]
. The elements wx
and
wy
are the chromaticity coordinates of the white point, and the
elements rx
, ry
, gx
,
gy
, bx
, and by
are the
chromaticity coordinates of the three primary colors.
If you specify Chromaticities
, you should also specify the
Gamma
name-value pair argument.
Example: 'Chromaticities',[0.312,0.329,0.002,0.002,0.001,0.001,0.115,0.312]
Data Types: double
Comment
— Comment to add to image
character vector | string scalar
Comment to add to the image, specified as the comma-separated pair consisting of
'Comment'
and a character vector or string scalar.
Copyright
— Copyright notice
character vector | string scalar
Copyright notice, specified as the comma-separated pair consisting of
'Copyright'
and a character vector or string scalar.
CreationTime
— Time of original image creation
character vector | string scalar
Time of original image creation, specified as a character vector or string scalar.
Description
— Description of image
character vector | string scalar
Description of the image, specified as the comma-separated pair consisting of
'Description'
and a character vector or string scalar.
Disclaimer
— Legal disclaimer
character vector | string scalar
Legal disclaimer, specified as the comma-separated pair consisting of
'Disclaimer'
and a character vector or string scalar.
Gamma
— File gamma
scalar
File gamma, specified as the comma-separated pair consisting of
'Gamma'
and a scalar.
Example: 'Gamma',2.2
ImageModTime
— Time of last image modification
serial date number | character vector or string scalar containing a date
Time of the last image modification, specified as the comma-separated pair
consisting of 'ImageModTime'
and a MATLAB serial date number or a character vector or string scalar of a date that
can be converted to a date vector using the datevec
function.
Values should be in Coordinated Universal Time (UTC).
The default ImageModTime
value is the time when you call
imwrite
.
Example: 'ImageModTime','17-Jan-2013 11:23:10'
Data Types: double
| char
| string
InterlaceType
— Interlacing scheme
'none'
(default) | 'adam7'
Interlacing scheme, specified as the comma-separated pair consisting of
'InterlaceType'
and either 'none'
for no
interlacing, or 'adam7'
to use the Adam7 algorithm.
Example: 'InterlaceType','adam7'
ResolutionUnit
— Unit for image resolution
'unknown'
(default) | 'meter'
Unit for image resolution, specified as the comma-separated pair consisting of
'ResolutionUnit'
and either 'unknown'
or
'meter'
. If you specify ResolutionUnit
, you
must include at least one of the XResolution
and
YResolution
name-value pair arguments. When the value of
ResolutionUnit
is 'meter'
, the
XResolution
and YResolution
values are
interpreted in pixels per meter.
Example: 'ResolutionUnit','meter','XResolution',1000
SignificantBits
— Number of bits to regard as significant
[]
(default) | scalar | vector
Number of bits in the data array to regard as significant, specified as the
comma-separated pair consisting of 'SignificantBits'
and a scalar
or a vector in the range [1,BitDepth
]. Depending on the output
image type, the value must be in the following form.
Image Type | Form of SignificantBits Value |
---|---|
Grayscale image without an alpha channel | Scalar |
Grayscale image with an alpha channel | 2-element vector |
Indexed image | 3-element vector |
Truecolor image without an alpha channel | 3-element vector |
Truecolor image with an alpha channel | 4-element vector |
Example: 'SignificantBits',[2,3]
Software
— Software used to create the image
character vector | string scalar
Software used to create the image, specified as the comma-separated pair
consisting of 'Software'
and a character vector or string
scalar.
Source
— Device used to create the image
character vector | string scalar
Device used to create the image, specified as the comma-separated pair consisting
of 'Source'
and a character vector or string scalar.
Transparency
— Pixels to consider transparent
[]
(default) | scalar in the range [0,1] | vector
Pixels to consider transparent when no alpha channel is used, specified as the
comma-separated pair consisting of 'Transparency'
and a scalar or a
vector. Depending on the output image, the value must be in the following form.
Image Type | Form of Transparency Value |
---|---|
Grayscale images | Scalar in the range [0,1], indicating the grayscale color to be considered transparent. |
Indexed images | Q- element vector of values in the range [0,1], where
Q is no larger than the colormap length and each value
indicates the transparency associated with the corresponding colormap entry.
In most cases, Q = 1 . |
Truecolor images | 3-element vector of RGB intensities in the range [0,1], indicating the truecolor color to consider transparent. |
Note
You cannot specify both 'Transparency'
and
'Alpha'
at the same time.
Example: 'Transparency',[1 1 1]
Data Types: double
Warning
— Warning of nature of content
character vector | string scalar
Warning of nature of content, specified as the comma-separated pair consisting of
'Warning'
and a character vector or string scalar.
XResolution
— Image resolution in horizontal direction
scalar
Image resolution in the horizontal direction, in pixels/unit, specified as the
comma-separated pair consisting of 'XResolution'
and a scalar.
Define the unit by specifying the ResolutionUnit
name-value pair
argument.
If you do not also specify YResolution
, then the
XResolution
value applies to both the horizontal and vertical
directions.
Example: 'XResolution',900
YResolution
— Image resolution in vertical direction
scalar
Image resolution in the vertical direction, in pixels/unit, specified as the
comma-separated pair consisting of 'XResolution'
and a scalar.
Define the unit by specifying the ResolutionUnit
name-value pair
argument.
If you do not also specify XResolution
, then the
YResolution
value applies to both the horizontal and vertical
directions.
Example: 'YResolution',900
In addition to the listed name-value pair arguments for PNG, you can use any parameter name that satisfies the PNG specification for keywords. That is, the name uses only printable characters, contains 80 or fewer characters, and does not contain leading or trailing spaces. The value corresponding to these user-specified names must be a character vector or string scalar that contains no control characters other than linefeed.
Alpha
— Transparency of each pixel
[]
(default) | matrix
Transparency of each pixel, specified as the comma-separated pair consisting of
'Alpha'
and a matrix with row and column dimensions the same as
those of the image data array.
Valid only for truecolor (m
-by-n
-by-3) image
data.
Data Types: double
| single
| uint8
| uint16
Type
— Image type
'standard'
(default) | 'rgb'
| 'rle'
Image type, specified as the comma-separated pair consisting of
'Type'
and one of the options in this table.
Value of Type | Description |
---|---|
'standard' (default) | Uncompressed, B-G-R color order for truecolor images |
'rgb' | Uncompressed, R-G-B color order for truecolor images |
'rle | Run-length encoding of 1-bit and 8-bit images |
Example: 'Type','rgb'
ColorSpace
— Color space representing color data
'rgb'
(default) | 'cielab'
| 'icclab'
Color space representing the color data, specified as the comma-separated pair
consisting of 'ColorSpace'
and one of these options:
'rgb'
'cielab'
'icclab'
Valid only when the image data array, A
, is truecolor
(m
-by-n
-by-3). To use the CMYK color space in
a TIFF file, do not use the 'ColorSpace'
name-value pair argument.
Instead, specify an m
-by-n
-by-4 image data
array.
imwrite
can write color image data that uses the
L*a*b* color space to TIFF files. The 1976 CIE
L*a*b* specification defines numeric values that represent
luminance (L*) and chrominance (a* and
b*) information. To store L*a*b* color
data in a TIFF file, the values must be encoded to fit into either 8-bit or 16-bit
storage. imwrite
can store L*a*b* color data
in a TIFF file using the following encodings:
CIELAB encodings — 8-bit and 16-bit encodings defined by the TIFF specification
ICCLAB encodings — 8-bit and 16-bit encodings defined by the International Color Consortium
The output class and encoding used by imwrite
depends on the
class of the input image data array and the ColorSpace
value, as
shown in the following table. (The 8-bit and 16-bit CIELAB encodings cannot be input
arrays because they use a mixture of signed and unsigned values and cannot be
represented as a single MATLAB array.)
Input Class and Encoding |
Value of |
Output Class and Encoding |
---|---|---|
8-bit ICCLAB Values are integers in the range [0 255]. L* values
are multiplied by |
' |
8-bit ICCLAB |
' |
8-bit CIELAB | |
16-bit ICCLAB Values are integers in the range [0, 65280]. L*
values are multiplied by |
' |
16-bit ICCLAB |
' |
16-bit CIELAB | |
Double-precision 1976 CIE L*a*b* values L* is in the dynamic range [0, 100]. a* and b* can take any value. Setting a* and b* to 0 (zero) produces a neutral color (gray). |
' |
8-bit ICCLAB |
' |
8-bit CIELAB |
Example: 'ColorSpace','cielab'
Compression
— Compression scheme
'packbits'
| 'none'
| 'lzw'
| 'deflate'
| 'jpeg'
| 'ccitt'
| 'fax3'
| 'fax4'
Compression scheme, specified as the comma-separated pair consisting of
'Compression'
and one of these options:
'packbits'
(default for nonbinary images)'none'
'lzw'
'deflate'
'jpeg'
'ccitt'
(binary images only, and the default for such images)'fax3'
(binary images only)'fax4'
(binary images only)
'jpeg'
is a lossy compression scheme; other compression modes
are lossless. Also, if you specify 'jpeg'
compression, you must
specify the 'RowsPerStrip'
parameter and the value must be a
multiple of 8.
Example: 'Compression','none'
Description
— Image description
character vector | string scalar
Image description, specified by the comma-separated pair consisting of
'Description'
and a character vector or string scalar. This is
the text that imfinfo
returns in the
ImageDescription
field for the output image.
Example: 'Description','Sample 2A301'
Resolution
— X- and Y-resolution
72 (default) | scalar | two-element vector
X- and Y-resolution, specified as the comma-separated pair consisting of
'Resolution'
and a scalar indicating both resolution, or a
two-element vector containing the X-Resolution and Y-Resolution.
Example: 'Resolution',80
Example: 'Resolution',[320,72]
Data Types: double
RowsPerStrip
— Number of rows to include in each strip
scalar
Number of rows to include in each strip, specified as the comma-separated pair
consisting of 'RowsPerStrip'
and a scalar. The default value is
such that each strip is about 8 kilobytes.
You must specify RowsPerStrip
if you specify
'jpeg'
compression. The value must be a multiple of 8.
Example: 'RowsPerStrip',16
Data Types: double
| single
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
WriteMode
— Writing mode
'overwrite'
(default) | 'append'
Writing mode, specified as the comma-separated pair consisting of
'WriteMode'
and either 'overwrite'
or
'append'
. In overwrite
mode,
imwrite
overwrites an existing file. In
append
mode, imwrite
adds a page to the
existing file.
Example: 'WriteMode','append'
Tips
For copyright information, see the
libtiffcopyright.txt
file.
Extended Capabilities
Thread-Based Environment
Run code in the background using MATLAB® backgroundPool
or accelerate code with Parallel Computing Toolbox™ ThreadPool
.
Usage notes and limitations:
imwrite
does not support reading Hierarchical Data Format (HDF), SVS, or TIFF files when you runimwrite
in the background usingbackgroundPool
or Parallel Computing Toolbox™Threadpool
.
For more information, see Run MATLAB Functions in Thread-Based Environment.
GPU Arrays
Accelerate code by running on a graphics processing unit (GPU) using Parallel Computing Toolbox™.
Usage notes and limitations:
This function accepts GPU arrays, but does not run on a GPU.
For more information, see Run MATLAB Functions on a GPU (Parallel Computing Toolbox).
Version History
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