imtool (Image Processing Toolbox User's Guide)

Image Processing Toolbox User's Guide

Display image in the Image Tool

Syntax

imtool
imtool(I)
imtool(I,[LOW HIGH])
imtool(RGB)
imtool(BW)
imtool(X,map)
imtool(filename)
hfig = imtool(...)
imtool close all
imtool(...,param1,val1,param2,val2,...)

Description

imtool opens a new Image Tool in an empty state. Use the File menu options Open or Import from Workspace to choose an image for display.

imtool(I) displays the intensity image I.

imtool(I,[LOW HIGH]) displays I as a grayscale intensity image, specifying the display range for I. The value LOW (and any value less than LOW) is displayed as black, the value HIGH (and any value greater than HIGH) is displayed as white. Values in between are displayed as intermediate shades of gray. imtool uses the default number of gray levels. If you use an empty matrix ([]) for [LOW HIGH], imtool uses [min(I(:)) max(I(:))]; the minimum value in I is displayed as black, and the maximum value is displayed as white.

imtool(RGB) displays the truecolor image RGB.

imtool(BW) displays the binary image BW. Values of 0 is displayed as black, and values of 1 is displayed as white.

imtool(X,map) displays the indexed image X with colormap map.

imtool(filename) displays the image contained in the graphics file filename. The file must contain an image that can be read by imread or dicomread. imtool calls imread or dicomread to read the image from the file, but the image data is not stored in the MATLAB workspace. If the file contains multiple images, the first one is displayed. The file must be in the current directory or on the MATLAB path.

hfig = imtool(...) returns a handle Hfig to the figure created by imtool. close(Hfig) closes the image tool.

imtool close all closes all image tools.

imtool(...,param1,val1,param2,val2,...) displays the image, specifying parameters and corresponding values that control various aspects of the image display. The following table lists all imshow parameters. Parameter names can be abbreviated, and case does not matter.

Parameter
Value

'DisplayRange'
Two-element vector [LOW HIGH] that controls the display range of an intensity image. See above for more details about how to set [LOW HIGH].
Note: Including the parameter name is optional, except when the image is specified by a filename. The syntax imtool(I,[LOW HIGH]) is equivalent to imtool(I,'DisplayRange',[LOW HIGH]). However, the 'DisplayRange' parameter must be specified when calling imtool with a filename, as in the syntax imtool(filename,'DisplayRange'[LOW HIGH]).

'InitialMagnification'
One of two text strings: 'adaptive' or 'fit' or a numeric scalar value that specifies the initial magnification used to display the image.
When set to 'adaptive', the entire image is visible on initial display. If the image is too large to display on the screen, imtool displays the image at the largest magnification that fits on the screen.
When set to 'fit', imtool scales the entire image to fit in the window.
When set to a numeric value, the value specifies the magnification as a percentage. For example, if you specify 100, the image is displayed at 100% magnification (one screen pixel for each image pixel).
By default, the initial magnification parameter is set to the value returned by iptgetpref('ImtoolInitialMagnification').

Parameter	Value
`'DisplayRange'`	Two-element vector `[LOW HIGH]` that controls the display range of an intensity image. See above for more details about how to set `[LOW HIGH]`. Note: Including the parameter name is optional, except when the image is specified by a filename. The syntax `imtool(I,[LOW HIGH])` is equivalent to `imtool(I,'DisplayRange',[LOW HIGH])`. However, the `'DisplayRange'` parameter must be specified when calling `imtool` with a filename, as in the syntax `imtool(filename,'DisplayRange'[LOW HIGH])`.
`'InitialMagnification'`	One of two text strings: `'adaptive'` or `'fit'` or a numeric scalar value that specifies the initial magnification used to display the image. When set to `'adaptive'`, the entire image is visible on initial display. If the image is too large to display on the screen, `imtool` displays the image at the largest magnification that fits on the screen. When set to `'fit'`, `imtool` scales the entire image to fit in the window. When set to a numeric value, the value specifies the magnification as a percentage. For example, if you specify 100, the image is displayed at 100% magnification (one screen pixel for each image pixel). By default, the initial magnification parameter is set to the value returned by `iptgetpref('ImtoolInitialMagnification')`.

Class Support

A truecolor image can be uint8, uint16, double, or single. An indexed image can be logical, uint8, double, or single. An intensity image can be logical, uint8, double, single, int16, or uint16. The input image must be nonsparse.

Related Toolbox Preferences

You can use the iptsetpref function to set the following toolbox preference that modifies the behavior of imtool.

'ImtoolInitialMagnification' controls the initial magnification for image display, unless you override it in a particular call by specifying imtool(...,'InitialMagnification',initial_mag).

For more information about these preferences, see the reference entry for iptsetpref.

Remarks

imshow is the toolbox's fundamental image display function, optimizing figure, axes, and image object property settings for image display. imtool provides all the image display capabilities of imshow but also provides access to several other tools for navigating and exploring images, such as the Pixel Region tool, Image Information tool, and the Adjust Contrast tool. imtool presents an integrated environment for displaying images and performing some common image processing tasks.

Examples

Display an image from a file.

```
imtool('board.tif')
```

Display an indexed image.

[X,map] = imread('trees.tif');
imtool(X,map)

Display an intensity image.

```
I = imread('cameraman.tif');
imtool(I)
```

Display an intensity image, adjusting the display range.

```
h = imtool(I,[0 80]);
close(h)
```

imsubtract imtophat