How to change imgae in imageLabelingSession.mat file

I have used Image labeler App to mark the labels. I saved the imageLabelingSession file and PixelLabelData files. Now I want to apply same PixelLabelData (groundtruth images) on other images which has same structure but different in terms of parameters(i used image processing method on thses images).

How can I repalce the image files in imageLabelingSession with out marking again.

Answer 1

[Raunak Gupta]

Hi,

I assume after doing the labeling you have exported the labels as a groundTruth object. The groundTruth object contains three field DataSource, LabelDefinitions and LabelData. You can replace the groundTruth.DataSource with a groundTruthDataSource object. This can be created by reading the replacement images into imageDatastore.

Below example code explains above steps:

% load groundTruth object created from exported labels 
load groundTruth 
% replaceImagedir :- directory where replacement images are stored 
replaceImds = imageDatastore(replaceImagedir); 
replaceDataSource = groundTruthDataSource(replaceImds); 
% Replacing the Datasource to the new images 
groundTruth.DataSource = replaceDataSource; 

[Raza Ali]

Thank you for sharing meaningful answer but while trying the above code i received an error.

>> D='D:\A\B\images'; %root of folder where new files are stored

>> replaceImagedir =dir(fullfile(D,'*.jpg'));

>> replaceImds = imageDatastore(replaceImagedir);

Error using imageDatastore (line 125)

Location must be a struct containing fields FileName, Size, and Offset.

[Raunak Gupta]

Hi,

You cannot give struct to imageDatastore as it doesn't take struct object (dir return a struct object naming all file in given path). You can give path directly to imageDatastore and mention the FileExtension as '.jpg' and it will create the datastore from it.

D='D:\A\B\images';
replaceImds = imageDatastore(D,'FileExtensions','.jpg');

You can read more here.

[Raza Ali]

Error using groundTruthDataSource/parseAndPopulateInputs (line 473)

The value of 'SourceName' is invalid. Expected input number 1, Data Source Name (Image Sequence, Video Name or Custom Source Name), to be one of these types:

char, string, cell

Instead its type was matlab.io.datastore.ImageDatastore.

Error in groundTruthDataSource (line 187)

parseAndPopulateInputs(this, varargin{:});

[Raunak Gupta]

Hi,

I think dot indexing is not supported to replace the property in groundTruth object. You can either use below command or a standalone function which can replace links.

newgroundTruth = groundTruth(replaceDataSource,oldgroundTruth.LabelDefinitions,oldgroundTruth.LabelData);

The standalone function is changeFilePaths.