Edit the labels in Ground Truth Image Labeler.

I had used the Ground Truth Image Labeler app before to label some images for pixel level segmentaion experiment using matlab 2018b. Now I am trying to edit those labels , for instance add another category to all of them but I am having a problem in loading them properly. good news is I still have the Images and the labels , bad news is I am confused with the gtruth mat file and how to recover the session . when I try to use Load>session> and choose the gTruth file I recieve this error message

' E:/ gTruth. mat' is not a valid Ground Truth Labeler session MAT file.

My questions are :

1- Can I recover the old session from Images+Labels only? or how van i creat a new session using those iamges and labels so i dont have to re-do all the labeling work again?

2- Can I use the same step above with different version of Matlab , say Matlab 2019B?

thanks

Answer 1

[Raunak Gupta]

Hi,

I assume you have done the labelling on one of the Ground Truth Labeler App or Image Labeler App in MATLAB R2018b. For importing the session or labels in R2019b and editing them, the labelling is required to be done in the same App you used on R2018b.

So, if the groundTruth is exported from Image Labeler App in R2018b it will only be get loaded in Image Labeler App in R2019b.

Although the labeled output object for both Apps is same that is groundTruth but since Ground Truth Labeler App is used for Video and Image Sequence Labeling, there will be an extra field in the label definition called Time for groundTruth generated from the Ground Truth Labeler App. Thus, loading the labels or session from Ground Truth Labeler app is not possible in Image Labeler App. Loading in the same App will not through any error.

Hope it helps.

[caesar]

thank you Raunak Gupta

That was helpful with regards to 2 in my post.

I would appreciete it if you can help me with 1.

Here are the things I know so far . The labeling process has been done on Image Labeler app on Matlab 2018a. I have the gTruth mat file and when I load it into Matlab I receive this message :

Warning: The data source points to one or more image files that cannot be found. Update the DataSource filenames using a valid groundTruthDataSource object.

what I did is :

gTruth.DataSource

results are

ans = 

  groundTruthDataSource with properties:

                      Source: {
                              'C:\Users\2164104a\Documents\MATLAB\Refined\image01(68).jpg';
                              'C:\Users\2164104a\Documents\MATLAB\Refined\image01(69).jpg';
                              'C:\Users\2164104a\Documents\MATLAB\Refined\image01(70).jpg'
                               ... and 110 more
                              }

next

    gTruth.LabelData.PixelLabelData

ans =

  113×1 cell array

    {'C:\Users\2164104a\Documents\MATLAB\PixelLabelData\Label_1.png'  }
    {'C:\Users\2164104a\Documents\MATLAB\PixelLabelData\Label_2.png'  }
    {'C:\Users\2164104a\Documents\MATLAB\PixelLabelData\Label_3.png'  }

I did make sure both images and labels are in those folders but when I load the images from the Image Labeler app then trying to ' Import Labels' and choosing the gTruth file i recieve this message :

Unable to load labels from gTruth.mat. the groundTruth object doesnt have a valid DataSource. Update the DataSource using a valid groundTruthDataSource object.

so I guess now my question is what is wrong with those images,labels and gTruth file? and how can I update the DataSource even though all data are still there

[Raunak Gupta]

Hi,

While recreating the problem above I have noticed that the folder in which the images are stored is the one where PixelLabelData directory will be formed. Right now in

gTruth.DataSource

I see that Images are in ~\MATLAB\Refined\ directory whereas labels are in ~\MATLAB. From here I can understand that you may have copy-pasted the PixelLabelData folder outside the folder named 'Refined'. You may change the file path that are set accidentally using changeFilePaths. Make sure the Labels and images are on the path mentioned in the gTruth.DataSource & gTruth.LabelData.PixelLabelData .

Hope this resolve the query.

[caesar]

thank you Raunak Gupta ,

I updated both the images source and labels source and managed to load them all. that is a huge relief for now.

Answer 2

[Md Shamim Hossain]

Many Thanks Raunak Gupta. You really have saved my time....!!