街景房屋编号（SVHN）数据集，可用于对象识别算法的真实图像数据集

SVHN是一个用于开发机器学习和对象识别算法的真实图像数据集，对数据预处理和格式化的要求最低。它可以被视为与MNIST在风格上相似（例如，图像是小的裁剪数字），但包含了一个数量级以上的标记数据（超过600000个数字的图像），并且来自一个更难、未解决的现实世界问题（识别自然场景图像中的数字和数字）。SVHN是从谷歌街景图片中的门牌号中获取的。 These are the original, variable-resolution, color house-number images with character level bounding boxes, as shown in the examples images above. (The blue bounding boxes in the example image are just for illustration purposes. The bounding box information are stored in digitStruct.mat instead of drawn directly on the images in the dataset.) Each tar.gz file contains the orignal images in png format, together with a digitStruct.mat file, which can be loaded using Matlab. The digitStruct.mat file contains a struct called digitStruct with the same length as the number of original images. Each element in digitStruct has the following fields: name which is a string containing the filename of the corresponding image. bbox which is a struct array that contains the position, size and label of each digit bounding box in the image. Eg: digitStruct(300).bbox(2).height gives height of the 2nd digit bounding box in the 300th image. Character level ground truth in an MNIST-like format. All digits have been resized to a fixed resolution of 32-by-32 pixels. The original character bounding boxes are extended in the appropriate dimension to become square windows, so that resizing them to 32-by-32 pixels does not introduce aspect ratio distortions. Nevertheless this preprocessing introduces some distracting digits to the sides of the digit of interest. Loading the .mat files creates 2 variables: X which is a 4-D matrix containing the images, and y which is a vector of class labels. To access the images, X(:,:,:,i) gives the i-th 32-by-32 RGB image, with class label y(i). Please cite the following reference in papers using this dataset: This dataset is provided for non-commercial use only. By downloading and using the dataset you agree to acknowledge it's source and cite the above papers in related publications. Please link to the authors' URL for this dataset as http://ufldl.stanford.edu/housenumbers.