insertObjectMask

Insert masks in image or video stream

Since R2020b

Syntax

RGB = insertObjectMask(I,BW)

RGB = insertObjectMask(I,maskstack)

RGB = insertObjectMask(___,Name=Value)

Description

RGB = insertObjectMask(I,BW) inserts a mask BW into the specified image I and returns the result as a truecolor image RGB.

RGB = insertObjectMask(I,maskstack) inserts a set of masks maskstack into the specified image I and returns the result as a truecolor image RGB.

RGB = insertObjectMask(___,Name=Value) specifies options using one or more name-value arguments in addition to any combination of arguments from previous syntaxes. For example, (MaskColor="red") sets the color of the mask to red.

Examples

Insert Masks with White Borders

Read an image into the workspace.

I = imread("visionteam1.jpg");

Load a stack of binary masks into the workspace.

load("visionteam1Maskstack.mat")

Insert the masks with white outlines into the image.

RGB = insertObjectMask(I,maskstack,LineColor="white",LineWidth=2);

Display the image with the masks inserted.

figure
imshow(RGB)

Insert Masks and Assign Unique Color to Each

Read an image into the workspace.

I = imread("visionteam1.jpg");

Load a stack of binary mask images.

load("visionteam1Maskstack.mat");

Insert the masks into the image and specify a unique color for each mask.

numMasks = size(maskstack,3);
RGB = insertObjectMask(I,maskstack,MaskColor=lines(numMasks));

Display the image with the inserted masks.

figure 
imshow(RGB)

Input Arguments

I — Input image

truecolor image | grayscale image

Input image, specified as a truecolor (RGB) image, m-by-n-by-3 array, or a grayscale image, m-by-n array.

Data Types: single | double | int16 | uint8 | uint16

BW — Input mask image

m-by-n logical matrix

Input mask image, specified as an m-by-n logical matrix.

Data Types: logical

maskstack — Stack of mask images

m-by-n-by-P logical array

Stack of mask images, specified as an m-by-n-by-P logical array, where P is the total number of masks in the stack.

maskstack has the same width and height as I.

Data Types: logical

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: LineColor="white" set the inserted line color to white.

MaskColor — Mask color

"green" (default) | character vector | cell array of character vectors | string scalar | string array | M-by-3 matrix

Mask color, specified as a character vector, cell array of character vectors, vector, or M-by-3 matrix of RGB values.

An RGB triplet is a three-element row vector whose elements specify the intensities of the red, green, and blue components of the color. The intensities must be in the range [0,1], for example, [0.4 0.6 0.7]. When using a data type of uint8, which is defined within the range of [0,255], conversions are necessary to ensure that the expected range is met. For example, to specify the previous vector, you must convert it by using uint8(255*[0.4 0.6 0.7]).

You can specify a different color for each mask or one color for all masks. To specify one color for all masks, set MaskColor to a color string or an [R G B] vector.

Specification	Format	Example
Specify one color for all shapes (or markers)	Short color name or color name	"r" "red"
	RGB triplet	[1 0 0]
Specify a color for each shape (or marker)	Vector of color names	["red","yellow","blue"]
	Three-column matrix of RGB triplets	[1 0 0 0 1 1 1 0 1 1 1 1]

Supported colors are listed in the table.

Color Name	Short Name	RGB Triplet	Appearance
"red"	"r"	[1 0 0]
"green"	"g"	[0 1 0]
"blue"	"b"	[0 0 1]
"cyan"	"c"	[0 1 1]
"magenta"	"m"	[1 0 1]
"yellow"	"y"	[1 1 0]
"black"	"k"	[0 0 0]
"white"	"w"	[1 1 1]

Color values must be specified in the range of the data type support that you use to specify them. For example, if you specify an input of double datatype, then values must be in the range [0,1]. If you specify an input of uint8 datatype, then values must be in the range [0 255]. For example, [0,0,1] and uint8([0,0,255]) are two formats for the same color blue.

Data Types: logical | uint8 | uint16 | int16 | double | single

Opacity — Opacity of mask

0.6 (default) | scalar in the range [0 1]

Opacity of mask, specified as a scalar value in the range [0 1]. The value 1 makes the mask completely opaque and the value 0 makes the mask completely transparent.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

LineColor — Color of mask borders

"auto" (default) | RGB triplet | ColorSpec

Color of mask borders, specified as one of these values:

• "auto" — LineColor uses the same value or values as MaskColor.

• P-by-3 matrix of RGB triplets, where P is the total number of masks

• P-element vector of MATLAB^® ColorSpec names

• 1-by-3 RGB triplet or scalar MATLAB ColorSpec name, specifying the color to use for all masks.

  For a description of RGB color and how to specify it, see MaskColor.

Data Types: single | double | int16 | uint8 | uint16 | logical | char | string

LineOpacity — Opacity of mask borders

1 (default) | 0

Opacity of the mask borders, specified as a scalar value in the range of [0 1].

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

LineWidth — Width of mask borders

1 (default) | positive scalar

Width of mask borders, specified as a positive scalar in pixels.

Data Types: single | double | int8 | int16 | int32 | int64 | uint8 | uint16 | uint32 | uint64

Output Arguments

RGB — Output image

truecolor image

Output image, returned as a truecolor image of same datatype as the input image, with the same m-by-n dimensions as I.

Tips

• When masks overlap and the same pixel is in more than one mask, maskstack(:,:,i) takes precedence over maskstack(:,:,j), where i < j.

• For better performance, set LineOpacity to 0 to disable drawing of the edges.

Extended Capabilities

C/C++ Code Generation

Generate C and C++ code using MATLAB® Coder™.

Usage notes and limitations:

• The value of the LineWidth parameter must be a compile-time constant.

• The values of the MaskColor and LineColor name-value arguments must be numeric. The MATLAB ColorSpec is not supported with code generation.

Version History

Introduced in R2020b

R2023b: Specify RGB color in the range [0,1]

Starting in R2023b, you can specify color with RGB values in the range [0,1].