如何在 MATLAB 中为神经网络提供测试样本？

Question

在 MATLAB 经典的螃蟹分类问题中，神经网络仅从提供的样本中选择测试样本。假设，如果我向神经网络提供 30 个样本，它会随机抽取其中的 5 个样本作为测试样本。

是否可以从用户端指定测试样本？

fid = fopen('/featureValues.csv');
C = textscan(fid,'%f%f%f%f%s','delimiter',',');  % Import data
fclose(fid);

%%
% The first 4 columns of data represent the image's features
% The 5th column represents the category of the image.

features = [C{1} C{2} C{3} C{4}]; % inputs to neural network

tiger = strncmpi(C{5}, 'tiger', 1);
lion = strncmpi(C{5}, 'lion', 1);
dino = strncmpi(C{5}, 'Dino', 1);

%Encoding the image categories
imCat = double([tiger lion dino]);                 % targets for neural network

% The next step is to preprocess the data into a form that can be used with
% a neural network.
%
% The neural network object in the toolbox expects the samples along
% columns and its features along rows. Our dataset has its samples along
% rows and its features along columns. Hence the matrices have to be
% transposed.

features = features';
imCat = imCat';

%% Building the Neural Network Classifier
% The next step is to create a neural network that will learn to identify
% the class of the images.
%
% Since the neural network starts with random initial weights, the results
% of this demo will differ slightly every time it is run. The random seed
% is set to avoid this randomness. However this is not necessary for your
% own applications.

rand('seed', 491218382)

%%
% A 1-hidden layer feed forward network is created with 20 neurons in the
% hidden layer.
%

net = newff(features,imCat,20); % Create a new feed forward network


% Now the network is ready to be trained.

[net,tr] = train(net,features,imCat);

%% Testing the Classifier
testInputs = features(:,tr.testInd);
testTargets = imCat(:,tr.testInd);

out = net(testInputs);        % Get response from trained network

[y_out,I_out] = max(out);
[y_t,I_t] = max(testTargets);

N = size(testInputs,2);               % Number of testing samples
fprintf('Total testing samples: %d\n', N);

Answer 1

Read here first where they explain how to use different data division patterns. From the question it seems that you are looking specifically for this approach 以便您可以按索引指定训练、验证和测试数据。

如何在 MATLAB 中为神经网络提供测试样本？

How to provide the test samples to neural network in MATLAB?

matlab

image-processing

neural-network