class copy() function don't copy all elements?

below code is a matlab example of custom datastore.

I edited the code to extract label information from imageDatastore.

If the part of 'obj.NumObservations = numel(obj.ImagesX.Files)' is commented, The suffle function part is broken.

But It outputs label(labelsX variable in code).

If the part of 'obj.NumObservations = numel(obj.ImagesX.Files)' is not commented, The suffle function part is not broken.

but It don't output label.

I think its problem is on obj.copy() in shuffle function.

If the part of 'obj.NumObservations = numel(obj.ImagesX.Files)' is commented, the suffle function part don't execute copy() function.

If the part of 'obj.NumObservations = numel(obj.ImagesX.Files)' is not commented, the suffle function part executes copy() function.

because the part of 'obj.NumObservations = numel(obj.ImagesX.Files)' is not commented, the label don't be outputted.

I think obj.copy() don't copy all element to NewObj, I think. Therefore the label don't come out.

what's the problem of obj.copy()? how to copy all elements? I think it is same manners in subset() fucntion.

So Why I comment the subset part in the class initial part.

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classdef cycleGanImageDatastore < matlab.io.Datastore & ...

matlab.io.datastore.Shuffleable

% cycleGanImageDatastore Create a Datastore to work with collections of images in 2 directory.

% IMDS = cycleGanImageDatastore(Xsize,Ysize,dirX, dirY) creates a Datastore,

% where Xsize/Ysize show the output size of images in X or Y directory

% and dirX/dirY are the path of the directory having image data to be used for training cycleGAN model.

% By calling read(IMDS), you can get unpaired images from each directory.

% Copyright 2019-2020 The MathWorks, Inc.

properties

Xsize

Ysize

DirX

DirY

ImagesX

ImagesY

MiniBatchSize

end

properties (SetAccess = protected)

NumObservations

end

methods

function obj = cycleGanImageDatastore(Xsize,Ysize,dirX, dirY)

obj.Xsize = Xsize;

obj.Ysize = Ysize;

obj.DirX = dirX;

obj.DirY = dirY;

obj.ImagesX = imageDatastore(obj.DirX,'IncludeSubfolders',true,'LabelSource','foldernames');

obj.ImagesY = imageDatastore(obj.DirY,"IncludeSubfolders",true,'LabelSource','foldernames');

obj.MiniBatchSize = 1;

obj.ImagesX.ReadSize = 1;

obj.ImagesY.ReadSize = 1;

%num = min(numel(obj.ImagesX.Files),numel(obj.ImagesY.Files));

%obj.ImagesX = obj.ImagesX.subset(1:num);

%obj.ImagesY = obj.ImagesY.subset(1:num);

%obj.NumObservations = numel(obj.ImagesX.Files);

end

function tf = hasdata(obj)

tf = obj.ImagesX.hasdata() && obj.ImagesY.hasdata();

end

function [data] = read(obj) % 画像の呼び出し:read a image

obj.ImagesX.ReadSize = obj.MiniBatchSize;

obj.ImagesY.ReadSize = obj.MiniBatchSize;

[ImagesX,infoX] = obj.ImagesX.read();

[ImagesY,infoY] = obj.ImagesY.read();

labelsX = infoX.Label;

labelsY = infoY.Label;

ImagesX = imresize(ImagesX,[128,128]);

ImagesY = imresize(ImagesY,[128,128]);

%imshow(ImagesX)

% 出力をCellでそろえる:set data type to cell

if ~iscell(ImagesX)

ImagesX = {ImagesX};

ImagesY = {ImagesY};

end

% 画像の前処理:do the preprocessing

%[transformedX, transformedY] = transformImagePair(obj,ImagesX, ImagesY);

transformedX = ImagesX;

transformedY = ImagesY;

% 正規化する:call function for normalization

[X, Y] = obj.normalizeImages(transformedX, transformedY);

% テーブル化して出力

data = table(X, Y);

end

function reset(obj)

obj.ImagesX.reset();

obj.ImagesY.reset();

end

function objNew = shuffle(obj)

objNew = obj.copy();

numObservations = objNew.NumObservations;

idx1 = randperm(numObservations);

objNew.ImagesX.Files = objNew.ImagesX.Files(idx1);

idx2 = randperm(numObservations);

objNew.ImagesY.Files = objNew.ImagesY.Files(idx2);

end

function [xOut, yOut] = normalizeImages(obj, xIn, yIn)

% 各最大値を元に正規化する:normalization with the max value

xOut = cellfun(@(x) rescale(x,'InputMin',0,'InputMax',255), xIn, 'UniformOutput', false);

yOut = cellfun(@(x) rescale(x,'InputMin',0,'InputMax',255), yIn, 'UniformOutput', false);

end

end

end

function [transformedX, transformedY] = transformImagePair(obj,ImagesX, ImagesY)

arguments

obj

ImagesX (:,1) cell

ImagesY (:,1) cell

end

finalSize = obj.Xsize(1:2); % 最終出力を指定:define the size of output

initialSize = finalSize + 30; % 最初にリサイズする大きさを指定:initial image size before cropping

mirror = rand(1) < 0.5; % 50%の確率で反転:flip or not

% データ拡張を適用:Apply augmentation

transformedX = cellfun(@(im) applyAugmentation(im, initialSize, finalSize, mirror), ...

ImagesX, ...

'UniformOutput', false);

transformedY = cellfun(@(im) applyAugmentation(im, initialSize, finalSize, mirror), ...

ImagesY, ...

'UniformOutput', false);

end

function imOut = applyAugmentation(imIn, initialSize, finalSize, mirror)

imInit = imresize(imIn, initialSize); % 画像をリサイズ

win = randomCropWindow2d(initialSize,finalSize);

imOut = imcrop(imInit,win);

if mirror

imOut = fliplr(imOut); % 左右反転:flip the image

end

end