insertObjectAnnotation
Annotate truecolor or grayscale image or video stream
Syntax
Description
Examples
Annotate Image with Numbers and Strings
Read image.
I = imread('board.tif');
Create labels of floating point numbers. The floating point numbers relate to confidence value labels.
label_str = cell(3,1); conf_val = [85.212 98.76 78.342]; for ii=1:3 label_str{ii} = ['Confidence: ' num2str(conf_val(ii),'%0.2f') '%']; end
Set the position for the rectangles as [x y width height].
position = [23 373 60 66;35 185 77 81;77 107 59 26];
Insert the labels.
RGB = insertObjectAnnotation(I,'rectangle',position,label_str,... 'TextBoxOpacity',0.9,'FontSize',18);
Display the annotated image.
figure
imshow(RGB)
title('Annotated chips');
Annotate Image with Integer Numbers
Read image.
I = imread('coins.png');
Set positions for the circles. The first two values represents the center at (x,y) and the third value is the radius.
position = [96 146 31;236 173 26];
Set the label to display the integers 5 and 10 (U.S. cents).
label = [5 10];
Insert the annotations.
RGB = insertObjectAnnotation(I,'circle',position,label,'LineWidth',3,'Color',{'cyan','yellow'},'TextColor','black');
Display.
figure
imshow(RGB)
title('Annotated coins');
Input Arguments
I
— Truecolor or grayscale image
M-by-N-by-3 truecolor | M-by-N 2-D grayscale
image
Truecolor or grayscale image, specified as an image or video stream. The input image can be either an M-by-N-by-3 truecolor or a M-by-N 2-D grayscale image.
Data Types: double
| single
| uint8
| uint16
| int16
shape
— Rectangle or circle annotation
‘rectangle
’ | ‘circle
’
Rectangle or circle annotation, specified as a character vector indicating the annotation shape.
Data Types: char
position
— Location and size of the annotation shape
M-by-3 matrix | M-by-4 matrix
Location and size of the annotation shape, specified as an M-by-3 or M-by-4 matrix. When you specify a rectangle, the position input matrix must be an M-by-4 matrix. Each row, M, specifies a rectangle as a four-element vector, [x y width height]. The elements, x and y, indicate the upper-left corner of the rectangle, and the width and height specify the size.
When you specify a circle, the position input matrix must be an M-by-3 matrix, where each row, M, specifies a three-element vector [x y r]. The elements, x and y, indicate the center of the circle and r specifies the radius.
Example: position = [50 120 75 75]
A rectangle with top-left corner located at x=50, y=120, with a width and height of 75 pixels.
Example: position = [96 146 31]
A circle with center located at x=96, y=146 and a radius of 31 pixels.
Example: position = [23 373 60 66;35 185 77 81;77 107
59 26]
Location and size for three rectangles.
label
— Label to associate with a shape
M-element numeric vector | string | categorical labels | cell array of ASCII character vectors
Label to associate with a shape, specified as an M numeric vector, string, categorical labels, or a cell array of ASCII character vectors. The character, string, or categorical labels must be encoded as ASCII characters. The cell array must be the of length equal to the number of shape positions. You can specify a scalar label for all shapes as a numeric scalar, string, or categorical.
Example: label = [5 10], where the function marks the first shape with the label, 5, and the second shape with the label, 10.
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: 'Color'
, 'white'
sets
the color for the label text box to white.
Font
— Font face of text
'LucidaSansRegular'
(default) | character vector | string scalar
Font face of text, specified as the comma-separated pair consisting
of 'Font
' and a character vector. The font face
must be one of the available truetype fonts installed on your system.
To get a list of available fonts on your system, type listTrueTypeFonts
at the MATLAB® command
prompt.
Data Types: char
FontSize
— Label text font size
12 (default) | integer in the range of [8
72
]
Label text font size, specified as the comma-separated pair
consisting of 'FontSize'
and an integer corresponding
to points in the range of [8 72].
Data Types: double
| single
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
LineWidth
— Shape border line width
1
(default)
Shape border line width, specified as the comma-separated pair
consisting of 'LineWidth
' and a positive scalar
integer in pixels.
Color
— Color for shape and corresponding label text box
'yellow'
(default) | character vector | string scalar | [R G B] vector | cell array | string array | M-by-3 matrix
Color for shape and for corresponding label text box, specified
as the comma-separated pair consisting of 'Color'
and
either a character vector, an [R G B] vector, a cell array, or an M-by-3
matrix.
To specify one color for all shapes, set this parameter to either a character vector or an [R G B] vector. To specify a color for each of the M shapes, set this parameter to a cell array of M character vectors. Alternatively, you can specify an M-by-3 matrix of RGB values for each annotation. RGB values must be in the range of the input image data type.
Supported colors: 'blue'
, 'green'
, 'cyan'
, 'red'
, 'magenta'
, 'black'
,
and 'white'
.
Data Types: char
| uint8
| uint16
| int16
| double
| single
| cell
TextColor
— Color of text in text label
'black'
(default) | character vector | string scalar | [R G B] vector | cell array | string array | M-by-3 matrix
Color of text in text label, specified as the comma-separated
pair consisting of 'TextColor'
and either a character
vector, an [R G B] vector, a cell array, or an M-by-3
matrix. To specify one color for all text, set this parameter to either
a character vector or an [R G B] vector. To specify a color for each
of the M text labels, set this parameter to a cell
array of M character vectors. Alternatively, you
can specify an M-by-3 matrix of RGB values for
each annotation. RGB values must be in the range of the input image
data type.
Supported colors: 'blue'
, 'green'
, 'cyan'
, 'red'
, 'magenta'
, 'yellow'
,
and 'white'
.
Data Types: char
| uint8
| uint16
| int16
| double
| single
| cell
TextBoxOpacity
— Opacity of text label box background
0.6 (default) | range of [0
1
]
Opacity of text label box background, specified as the comma-separated
pair consisting of 'TextBoxOpacity'
and a scalar
defining the opacity of the background of the label text box. Specify
this value in the range of 0
to 1
.
Data Types: double
| single
| int8
| int16
| int32
| int64
| uint8
| uint16
| uint32
| uint64
Output Arguments
RGB
— Truecolor or grayscale image with annotation
M-by-N-by-3 truecolor
Truecolor image with annotation, returned as an image or video stream.
Data Types: double
| single
| uint8
| uint16
| int16
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using MATLAB® Coder™.
Usage notes and limitations:
Input image must be bounded. See Specify Upper Bounds for Variable-Size Arrays (MATLAB Coder).
See System Objects in MATLAB Code Generation (MATLAB Coder).
Version History
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