|
|
| Line 5: |
Line 5: |
| | === Usage === | | === Usage === |
| | | | |
| - | The image and label data is stored in a binary format described on the website. For your convenience, two MATLAB functions for extracting the data are provided below. | + | The image and label data is stored in a binary format described on the website. For your convenience, we have provided two MATLAB helper functions for extracting the data. These functions are available at [[http://ufldl.stanford.edu/wiki/resources/mnistHelper.zip]]. |
| - | | + | |
| - | For loading the images:
| + | |
| - | <syntaxhighlight>
| + | |
| - | function images = loadMNISTImages(filename)
| + | |
| - | %loadMNISTImages returns a 28x28x[number of MNIST images] matrix
| + | |
| - | %containing the MNIST images
| + | |
| - | | + | |
| - | fp = fopen(filename, 'rb');
| + | |
| - | assert(fp ~= -1, ['Could not open ', filename, '']);
| + | |
| - | | + | |
| - | magic = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | assert(magic == 2051, ['Bad magic number in ', filename, '']);
| + | |
| - | | + | |
| - | numImages = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | numRows = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | numCols = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | | + | |
| - | images = fread(fp, inf, 'unsigned char');
| + | |
| - | images = reshape(images, numCols, numRows, numImages);
| + | |
| - | images = permute(images,[2 1 3]);
| + | |
| - | | + | |
| - | fclose(fp);
| + | |
| - | | + | |
| - | end
| + | |
| - | </syntaxhighlight>
| + | |
| - | | + | |
| - | For loading the labels:
| + | |
| - | <syntaxhighlight>
| + | |
| - | function labels = loadMNISTLabels(filename)
| + | |
| - | %loadMNISTLabels returns a [number of MNIST images]x1 matrix containing
| + | |
| - | %the labels for the MNIST images
| + | |
| - | | + | |
| - | fp = fopen(filename, 'rb');
| + | |
| - | assert(fp ~= -1, ['Could not open ', filename, '']);
| + | |
| - | | + | |
| - | magic = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | assert(magic == 2049, ['Bad magic number in ', filename, '']);
| + | |
| - | | + | |
| - | numLabels = fread(fp, 1, 'int32', 0, 'ieee-be');
| + | |
| - | | + | |
| - | labels = fread(fp, inf, 'unsigned char');
| + | |
| - | | + | |
| - | assert(size(labels,1) == numLabels, 'Mismatch in label count');
| + | |
| - | | + | |
| - | fclose(fp);
| + | |
| - | | + | |
| - | end
| + | |
| - | </syntaxhighlight>
| + | |
| | | | |
| | As an example of how to use these functions, you can check the images and labels using the following code: | | As an example of how to use these functions, you can check the images and labels using the following code: |
