remove image from imageDatastore

I often encounter the need for excluding images from an imageDatastore object. One could remove the image from the corresponding file system directory and create the imageDatastore again, but that should not be the default way. How do I remove a single image once the imageDatastore has been defined?

Answer 1

[karim botros]

I have been looking for the same issue, and i found an easy work around to remove specific images from the imagedatastore

where {1,1} is the index of the data you want to delete

data.Files = setdiff(data.Files,data.Files{1,1})

[Atsushi Ueno]

imageDatastore内のimageの削除 - (mathworks.com)

setdiff function removes only the relevant "Files" field and no other fields in this case.

The image data store object function that corresponds to the setdiff function is the subset function that has been introduced in R2019a.

You see "Files" and "Labels" field has been deleted as expected in the example below.

imds = imageDatastore(fullfile(matlabroot,"toolbox","matlab"),...
"IncludeSubfolders",true,"FileExtensions",".tif","LabelSource","foldernames")

imds = 
  ImageDatastore with properties:

                       Files: {
                              '/MATLAB/toolbox/matlab/demos/example.tif';
                              '/MATLAB/toolbox/matlab/imagesci/corn.tif'
                              }
                     Folders: {
                              '/MATLAB/toolbox/matlab'
                              }
                      Labels: [demos; imagesci]
    AlternateFileSystemRoots: {}
                    ReadSize: 1
      SupportedOutputFormats: ["png"    "jpg"    "jpeg"    "tif"    "tiff"]
         DefaultOutputFormat: "png"
                     ReadFcn: @readDatastoreImage

delimg = matches(imds.Files, imds.Files{1,1});
subimds = subset(imds, ~delimg)

subimds = 
  ImageDatastore with properties:

                       Files: {
                              '/MATLAB/toolbox/matlab/imagesci/corn.tif'
                              }
                     Folders: {
                              '/MATLAB/toolbox/matlab'
                              }
    AlternateFileSystemRoots: {}
                    ReadSize: 1
                      Labels: imagesci
      SupportedOutputFormats: ["png"    "jpg"    "jpeg"    "tif"    "tiff"]
         DefaultOutputFormat: "png"
                     ReadFcn: @readDatastoreImage