Pytorch中图像预处理相关函数

这篇分类总结比较完整
数据处理是模型训练之前的必备的一步，在Pytorch的TORCHVISION.TRANSFORMS.TRANSFORMS包含下面一下图像处理的函数（transform中的函数主要是处理PIL格式图像）：

Compose

Args:transforms (list of ``Transform`` objects): list of transforms to compose.

"Composes several transforms together” 组合几种不同的变形方法

ToTensor

Convert a PIL Image or numpy.ndarray to tensor. Converts a PIL Image or numpy.ndarray (H x W x C) in the range
[0, 255] to a torch.FloatTensor of shape (C x H x W) in the range [0.0, 1.0]。将PIL图像或者numpy.ndarry类型数据转成tensor.

ToPILImage

Convert a tensor or an ndarray to PIL Image.
Converts a torch.*Tensor of shape C x H x W or a numpy ndarray of shape H x W x C to a PIL Image while preserving the value range.

Normalize 有参数（mean,std）
处理的数据类型是tensor类型

Normalize a tensor image with mean and standard deviation.

Args:mean (sequence): Sequence of means for each channel.std (sequence): Sequence of standard deviations for each channel.

Given mean: (M1,...,Mn) and std: (S1,..,Sn) for n channels, this transform will normalize each channel of the input torch.*Tensor i.e. input[channel] = (input[channel] - mean[channel]) / std[channel]

Resize

Resize the input PIL Image to the given size,默认采用PIL.Image.BILINEAR插值法。

Args:size (sequence or int): Desired output size. If size is a sequence like(h, w), output size will be matched to this. If size is an int,smaller edge of the image will be matched to this number.i.e, if height > width, then image will be rescaled to(size * height / width, size)interpolation (int, optional): Desired interpolation. Default is``PIL.Image.BILINEAR``

Scale

推荐换成Resize

CenterCrop 参数（目标尺寸）

Crops the given PIL Image at the center
Args:
size (sequence or int): Desired output size of the crop. If size is an
int instead of sequence like (h, w), a square crop (size, size) is
made

Pad the given PIL Image on all sides with the given “pad” value
Args:
padding (int or tuple):
fill (int or tuple):
padding_mode (str):

Lambda

Apply a user-defined lambda as a transform
Args:
lambd (function): Lambda/function to be used for transform.

RandomTransforms

Base class for a list of transformations with randomness
Args:
transforms (list or tuple): list of transformations

RandomApply

Apply randomly a list of transformations with a given probability
Args:
transforms (list or tuple): list of transformations
p (float): probability

RandomOrder

Apply a list of transformations in a random order

RandomChoice

Apply single transformation randomly picked from a list

RandomCrop

Crop the given PIL Image at a random location.

Args:size (sequence or int)padding (int or sequence, optional):pad_if_needed (boolean)fillpadding_mode

RandomHorizontalFlip

Horizontally flip the given PIL Image randomly with a given probability.

 Args:p (float): probability of the image being flipped. Default value is 0.5

RandomVerticalFlip

Verticallly flip the given PIL Image randomly with a given probability.

 Args:p (float): probability of the image being flipped. Default value is 0.5

RandomPerspective

Performs Perspective transformation of the given PIL Image randomly with a given probability.

RandomResizedCrop

Crop the given PIL Image to random size and aspect ratio

RandomSizedCrop

废弃

FiveCrop

Crop the given PIL Image into four corners and the central crop

TenCrop

Five Crop后翻转（默认是水平翻转）

LinearTransformation

Transform a tensor image with a square transformation matrix and a mean_vector computed
offline

ColorJitter

Randomly change the brightness, contrast and saturation of an image.
args:brightness=0, contrast=0, saturation=0, hue=0

RandomRotation

Rotate the image by angle
args:degrees, resample=False, expand=False, center=None

RandomAffine

Random affine transformation of the image keeping center invariant
degrees, translate=None, scale=None, shear=None, resample=False, fillcolor=0

Grayscale

Convert image to grayscale.
args:num_output_channels=1

RandomGrayscale

Randomly convert image to grayscale with a probability of p (default 0.1)

Pytorch中图像预处理相关函数相关推荐

关于MNN中图像预处理
MNN工程化中,首先遇到图像预处理,其中要做的是对图像归一化,这里不需要我们自己用代码实现,MNN自动帮我们处理,代码如下,根据MNN回复,处理公式是 dst = (img - mean) * nor ...
深度学习中图像预处理均值
图像中的均值,均方差等名字解释均值表示信号中直流分量的大小,一般用E(x)表示,其公式为: 对于高斯白噪声而言,其均值为0. 均方值表示信号平方后的均值,一般用E(x^2)表示,一般是用来表示信 ...
PyTorch框架学习六——图像预处理transforms（二）
PyTorch框架学习六--图像预处理transforms(二) (续)二.transforms的具体方法 4.图像变换 (1)尺寸变换:transforms.Resize() (2)标准化:tran ...
PyTorch框架学习五——图像预处理transforms（一）
PyTorch框架学习五--图像预处理transforms(一) 一.transforms运行机制二.transforms的具体方法 1.裁剪 (1)随机裁剪:transforms.RandomCr ...
pytorch —— 图像预处理模块（Transforms）
transforms运行机制 torchvision是pytorch的计算机视觉工具包,在torchvision中有三个主要的模块: torchvision.transforms,常用的图像预处理方法 ...
PyTorch中的数据输入和预处理
文章目录 PyTorch中的数据输入和预处理数据载入类映射类型的数据集 torchvision工具包的使用可迭代类型的数据集总结 PyTorch中的数据输入和预处理数据载入类在使用PyTo ...
PyTorch系列入门到精通——图像预处理transforms
PyTorch系列入门到精通--图像预处理transforms
pytorch 图像预处理之减去均值，除以方差
在使用 torchvision.transforms进行数据处理时我们经常进行的操作是: transforms.Normalize((0.485,0.456,0.406), (0.229,0.224, ...
Pytorch中CNN图像回归问题预测值都一样
** Pytorch中CNN图像回归问题预测值都一样 ** 上网也查阅了许多资料,然后对比各种方法都试了一遍,归结为以下几点: 1.出现预测值都一样的情况,一般都是在某一层梯度消失了,然后导致输入到下 ...

Pytorch中图像预处理相关函数

Pytorch中图像预处理相关函数相关推荐

最新文章

热门文章