MeanSquares

Mean square error metric configuration

Description

A `MeanSquares` object describes a mean square error metric configuration that you pass to the function `imregister` to solve image registration problems.

Creation

You can create a `MeanSquares` object using the following methods:

• `imregconfig` — Returns a `MeanSquares` object paired with an appropriate optimizer for registering monomodal images

• Entering

`metric = registration.metric.MeanSquares;`
on the command line creates a `MeanSquares` object

Examples

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Create a `MeanSquares` object and use it to register two images with similar brightness and contrast.

Read the reference image and create an unregistered copy.

```fixed = imread('pout.tif'); moving = imrotate(fixed,5,'bilinear','crop');```

View the misaligned images.

`imshowpair(fixed,moving,'Scaling','joint');`

Create the metric configuration object suitable for registering monomodal images.

`metric = registration.metric.MeanSquares`
```metric = registration.metric.MeanSquares This class has no properties. ```

Create the optimizer configuration object.

`optimizer = registration.optimizer.RegularStepGradientDescent;`

Modify the optimizer configuration to get more precision.

```optimizer.MaximumIterations = 300; optimizer.MinimumStepLength = 5e-4;```

Perform the registration.

`movingRegistered = imregister(moving,fixed,'rigid',optimizer,metric);`

View the registered images.

`imshowpair(fixed, movingRegistered,'Scaling','joint');`

Tips

• The mean squares metric is an element-wise difference between two input images. The ideal value is zero. You can examine the computed values of mean square error if you enable `'DisplayOptimization'` when you call `imregister`. For example, ```movingRegistered = imregister(moving,fixed,'rigid',optimizer,metric,'DisplayOptimization',true);```

Algorithms

The mean squares image similarity metric is computed by squaring the difference of corresponding pixels in each image and taking the mean of the squared differences.

Version History

Introduced in R2012a

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