function [one_feat_sps, weight_pool_info]=do_sp_pooling(one_feat_img, one_sp_info) img_size=size(one_feat_img); num_units=img_size(1)*img_size(2); dim=img_size(3); one_feat_img=reshape(one_feat_img, [num_units dim]); img_size_org=one_sp_info.img_size; pixel_ind_map=reshape([1: num_units], [img_size(1) img_size(2)]); pixel_ind_map_org=imresize(pixel_ind_map, img_size_org, 'nearest'); pixel_ind_sps=one_sp_info.pixel_ind_sps; num_sp=numel(pixel_ind_sps); weight_pool_info=zeros([num_sp, num_units], 'like', one_feat_img); for idx_sp=1:num_sp pixel_ind_sp_one=pixel_ind_sps{idx_sp}; ind_pixels_in_map=pixel_ind_map_org(pixel_ind_sp_one); [ind_units,~,uniqueIndex] = unique(ind_pixels_in_map); frequency = accumarray(uniqueIndex(:),1)./numel(ind_pixels_in_map); frequency=single(frequency); freq_one_sp=zeros(1, num_units, 'single'); freq_one_sp(ind_units)=frequency; weight_pool_info(idx_sp, :)=freq_one_sp; end one_feat_sps=weight_pool_info*one_feat_img; end, 根据上述代码归纳出所有公式
时间: 2023-09-11 16:08:53 浏览: 29
根据上述代码,可以得到超像素池化的公式如下:
1. 将输入的特征图$\mathbf{X}\in\mathbb{R}^{H\times W\times D}$重塑为$\mathbf{X}'\in\mathbb{R}^{HW\times D}$。
2. 对于每个超像素$\mathbf{S}_i$,找到其包含的像素坐标集合$\mathcal{P}_i$,计算每个像素在超像素中的权重:
$$w_{ij}=\begin{cases} \frac{1}{|\mathcal{P}_i|}, & i\in\mathcal{P}_i \\ 0, & \text{otherwise} \end{cases}$$
其中,$j$表示输入特征图中的像素索引。
3. 将每个超像素的权重向量$\mathbf{w}_i\in\mathbb{R}^{HW}$与输入特征图$\mathbf{X}'$相乘,得到超像素池化后的特征向量$\mathbf{s}_i\in\mathbb{R}^D$:
$$\mathbf{s}_i=\mathbf{w}_i\mathbf{X}'$$
4. 将所有的超像素池化后的特征向量$\mathbf{s}_i$按行堆叠,得到输出的特征图$\mathbf{Y}\in\mathbb{R}^{N\times D}$,其中$N$为超像素的数量。
相关问题
function [one_feat_sps, weight_pool_info]=do_sp_pooling(one_feat_img, one_sp_info) img_size=size(one_feat_img); num_units=img_size(1)*img_size(2); dim=img_size(3); one_feat_img=reshape(one_feat_img, [num_units dim]); img_size_org=one_sp_info.img_size; pixel_ind_map=reshape([1: num_units], [img_size(1) img_size(2)]); pixel_ind_map_org=imresize(pixel_ind_map, img_size_org, 'nearest'); pixel_ind_sps=one_sp_info.pixel_ind_sps; num_sp=numel(pixel_ind_sps); weight_pool_info=zeros([num_sp, num_units], 'like', one_feat_img); for idx_sp=1:num_sp pixel_ind_sp_one=pixel_ind_sps{idx_sp}; ind_pixels_in_map=pixel_ind_map_org(pixel_ind_sp_one); [ind_units,~,uniqueIndex] = unique(ind_pixels_in_map); frequency = accumarray(uniqueIndex(:),1)./numel(ind_pixels_in_map); frequency=single(frequency); freq_one_sp=zeros(1, num_units, 'single'); freq_one_sp(ind_units)=frequency; weight_pool_info(idx_sp, :)=freq_one_sp; end one_feat_sps=weight_pool_info*one_feat_img; end将上述代码转换为pytorch代码,并可视化超像素的索引】
以下是将给定的 MATLAB 代码转换为 PyTorch 代码的过程:
```
import torch
import torch.nn.functional as F
import numpy as np
from scipy import ndimage
def do_sp_pooling(one_feat_img, one_sp_info):
img_size = one_feat_img.shape
num_units = img_size[0] * img_size[1]
dim = img_size[2]
one_feat_img = one_feat_img.reshape(num_units, dim)
img_size_org = one_sp_info['img_size']
pixel_ind_map = np.arange(num_units).reshape(img_size[0], img_size[1])
pixel_ind_map_org = ndimage.zoom(pixel_ind_map, [img_size_org[0]/img_size[0], img_size_org[1]/img_size[1]], order=0)
pixel_ind_sps = one_sp_info['pixel_ind_sps']
num_sp = len(pixel_ind_sps)
weight_pool_info = torch.zeros((num_sp, num_units), dtype=one_feat_img.dtype, device=one_feat_img.device)
for idx_sp in range(num_sp):
pixel_ind_sp_one = pixel_ind_sps[idx_sp]
ind_pixels_in_map = pixel_ind_map_org[pixel_ind_sp_one]
_, uniqueIndex = np.unique(ind_pixels_in_map, return_inverse=True)
frequency = np.bincount(uniqueIndex) / len(ind_pixels_in_map)
frequency = frequency.astype(one_feat_img.dtype)
freq_one_sp = torch.zeros(num_units, dtype=one_feat_img.dtype, device=one_feat_img.device)
freq_one_sp[ind_pixels_in_map] = torch.tensor(frequency, dtype=one_feat_img.dtype, device=one_feat_img.device)
weight_pool_info[idx_sp, :] = freq_one_sp
one_feat_sps = torch.mm(weight_pool_info, one_feat_img)
return one_feat_sps, weight_pool_info
```
这里我们使用了 PyTorch 库中的相关函数来实现对应功能,同时为了可视化超像素的索引,我们可以在函数中增加一些代码:
```
def do_sp_pooling(one_feat_img, one_sp_info):
img_size = one_feat_img.shape
num_units = img_size[0] * img_size[1]
dim = img_size[2]
one_feat_img = one_feat_img.reshape(num_units, dim)
img_size_org = one_sp_info['img_size']
pixel_ind_map = np.arange(num_units).reshape(img_size[0], img_size[1])
pixel_ind_map_org = ndimage.zoom(pixel_ind_map, [img_size_org[0]/img_size[0], img_size_org[1]/img_size[1]], order=0)
pixel_ind_sps = one_sp_info['pixel_ind_sps']
num_sp = len(pixel_ind_sps)
weight_pool_info = torch.zeros((num_sp, num_units), dtype=one_feat_img.dtype, device=one_feat_img.device)
for idx_sp in range(num_sp):
pixel_ind_sp_one = pixel_ind_sps[idx_sp]
ind_pixels_in_map = pixel_ind_map_org[pixel_ind_sp_one]
_, uniqueIndex = np.unique(ind_pixels_in_map, return_inverse=True)
frequency = np.bincount(uniqueIndex) / len(ind_pixels_in_map)
frequency = frequency.astype(one_feat_img.dtype)
freq_one_sp = torch.zeros(num_units, dtype=one_feat_img.dtype, device=one_feat_img.device)
freq_one_sp[ind_pixels_in_map] = torch.tensor(frequency, dtype=one_feat_img.dtype, device=one_feat_img.device)
weight_pool_info[idx_sp, :] = freq_one_sp
# 可视化超像素的索引
img_sp = np.zeros_like(pixel_ind_map_org)
img_sp[pixel_ind_sp_one//img_size[1], pixel_ind_sp_one%img_size[1]] = 1
img_sp = ndimage.binary_dilation(img_sp, iterations=1)
img_sp = np.where(img_sp, idx_sp+1, 0)
img_sp = ndimage.zoom(img_sp, [img_size[0]/img_size_org[0], img_size[1]/img_size_org[1]], order=0)
plt.imshow(img_sp, cmap='jet', alpha=0.3, vmin=0, vmax=num_sp)
one_feat_sps = torch.mm(weight_pool_info, one_feat_img)
return one_feat_sps, weight_pool_info
```
这里我们使用 matplotlib 库来绘制可视化结果,以 jet 颜色映射来表示超像素的索引。
import torch import torch.nn.functional as F import numpy as np from scipy import ndimage def do_sp_pooling(one_feat_img, one_sp_info): img_size = one_feat_img.shape num_units = img_size[0] * img_size[1] dim = img_size[2] one_feat_img = one_feat_img.reshape(num_units, dim) img_size_org = one_sp_info['img_size'] pixel_ind_map = np.arange(num_units).reshape(img_size[0], img_size[1]) pixel_ind_map_org = ndimage.zoom(pixel_ind_map, [img_size_org[0]/img_size[0], img_size_org[1]/img_size[1]], order=0) pixel_ind_sps = one_sp_info['pixel_ind_sps'] num_sp = len(pixel_ind_sps) weight_pool_info = torch.zeros((num_sp, num_units), dtype=one_feat_img.dtype, device=one_feat_img.device) for idx_sp in range(num_sp): pixel_ind_sp_one = pixel_ind_sps[idx_sp] ind_pixels_in_map = pixel_ind_map_org[pixel_ind_sp_one] _, uniqueIndex = np.unique(ind_pixels_in_map, return_inverse=True) frequency = np.bincount(uniqueIndex) / len(ind_pixels_in_map) frequency = frequency.astype(one_feat_img.dtype) freq_one_sp = torch.zeros(num_units, dtype=one_feat_img.dtype, device=one_feat_img.device) freq_one_sp[ind_pixels_in_map] = torch.tensor(frequency, dtype=one_feat_img.dtype, device=one_feat_img.device) weight_pool_info[idx_sp, :] = freq_one_sp one_feat_sps = torch.mm(weight_pool_info, one_feat_img) return one_feat_sps, weight_pool_info,根据上述代码,给出一个详尽的流程
这段代码实现了SP(super-pixel)Pooling的过程,其流程如下:
1.导入必要的库:torch,numpy和scipy中的ndimage。
2.定义一个名为do_sp_pooling的函数,该函数接收两个参数:一个特征图和一个super-pixel信息字典。
3.获取特征图的大小(img_size)和维度(dim),并将特征图重新调整为num_units * dim的形状。
4.获取原始图像的大小(img_size_org)和像素索引映射(pixel_ind_map_org),并使用ndimage.zoom函数将像素索引映射重新调整为原始图像的大小。
5.获取super-pixel信息中的像素索引(pixel_ind_sps)和super-pixel数量(num_sp)。
6.创建一个形状为num_sp * num_units的零张量weight_pool_info,用于存储每个super-pixel对应的像素的权重信息。
7.对于每个super-pixel:
a.获取该super-pixel的像素索引(pixel_ind_sp_one)。
b.使用像素索引映射获取每个像素在像素索引映射中的索引(ind_pixels_in_map)。
c.使用np.unique函数计算ind_pixels_in_map中的唯一值,并返回这些唯一值和它们在ind_pixels_in_map中的索引(uniqueIndex)。
d.使用np.bincount函数计算uniqueIndex中每个唯一值出现的频率,并将其除以ind_pixels_in_map的长度。
e.创建一个零张量freq_one_sp,其形状为num_units,用于存储当前super-pixel的像素在特征图中的权重信息。
f.将频率信息转换为张量,并将其存储到freq_one_sp中,使用ind_pixels_in_map作为索引。
g.将freq_one_sp存储到weight_pool_info的当前super-pixel行中。
8.将weight_pool_info与one_feat_img相乘,得到每个super-pixel的特征表示one_feat_sps。
9.返回one_feat_sps和weight_pool_info。