# Questions tagged [convolution]

For use when discussing the commutative and linear, but not associative operator interpreted on functions and distributions.

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### Output of a convolutional layer

Is the calculated output correct?
1 vote
23 views

### What are the general rules or principles for finding matrix operations that are used as filters in convolutional neural networks?

Is there a set of rules or guidelines for designing filters for convolutional neural networks? For example, a 3 x 3 layer with ones in the first column, zeroes in the second, and negative ones in the ...
48 views

### Shape of Flattened Layer in CNN

If I have a convolutional layer with dimension (5,5,4), (i.e, 4 no. of 5x5x1 feature maps), what will be the dimension of the flattened layer, if I apply flattening ...
52 views

### What neural network architecture would help me model a spectrogram?

I'm really a novice working with these technologies and I'm struggling to design a neural network that is powerful enough to model a spectrogram. For a personal project, I'm working on a spectrogram ...
21 views

### How does the use of 1x1 convolutional layers represent permutation in the GLOW model?

I am currently reading the GLOW paper (found here) and I can not understand how the authors claim that the use of 1x1 convolutional layers is equivalent to permutation holds true. I understand how a ...
1 vote
39 views

### How to align the description of a convolutional neural network in keras with wikipedia's conceptual model?

I was going through the introductory guide to convolutional neural networks in tensor flow here And I was trying to logically map some of the code I saw to my actual understanding of how convolutional ...
17 views

### How is the number of channels in a convolutional layer shrinked or expanded?

I know in order to shrink or expand the number of channels a 1x1 convolution is performed. I need to clarify the following: is the 1x1 convolution(s) just a matrix multiplication between the image ...
21 views

### How to backpropagate transposed convolution with stride and padding

Please, help! I have deadlines and I do not have time to figure out the topic on my own. And now about the problem. I'm currently trying to figure out back propagation in transposed convolution. I ...
69 views

### Multi-channel convolution in Tensorflow

Suppose I have a sequence data of size $B \times N \times d$ where $B$ is the batch size, $N$ is the sequence length, and $d$ is the dimension or the number of features. Suppose I want to do 1D ...
267 views

### Transpose Convolution Output Size

I have been learning GAN (Generative Adversarial Networks) lately and having a hard time understanding the output size for transpose convolution. Let's say I am using a Tensor of [1, 64, 1, 1] as an ...
99 views

### Transposed Convolution in PyTorch Visualisation

I am trying to visualize the output of the transpose convolution in pytorch to better understand the operation. Here is my code, inputs and output images as well: ...
98 views

### How to select best kernel_size and max_pool_size in CNN1D

I have data with shape size 1,89. setup kernel_size = 3 and pool_size = 2 on the conv1d layer. However, the model is not able to predict the peak well. i think the problem is because the kernel_size ...
480 views

### CNN model why is ReLu used in Conv1D layer and in the first Dense Layer?

I have a problem. I have a CNN model which is used for an NLP problem. This is written in Python. I have questions about this, which I can't find an answer to. Why is ReLu used inside the Conv1D ...
51 views

### Transpose Convolution feature extraction

Convolution extracts high-level features, but what about Transpose Convolution (or De/Up-Convolution)? Does it behave exactly the opposite? Does it generate lower-level features?
20 views

### why layer of dimension 1 is outputting image of size n

I am studying a model where landmarks from an image are calculated. The work comes from Convolutional Experts Constrained Local Model for 3D Facial Landmark Detection. I need to confirm why the ...
20 views

### NCHW input matrix to Dm conversion logic for convolution in cuDNN

I have been trying to understand the convolution lowering operation shown in the cuDNN paper. I was able to understand most of it by reading through and mapping various parameters to the image below. ...
24 views

### Inbetween CNN and MLP: neural network architecture for "close to convolutional" problem?

I am looking to approximate an (expensive to calculate precisely) forward problem using a NN. Input and output are vectors of identical length. Although not linear, the output somewhat resembles a ...
1 vote
316 views

### Why does the 1st derivative appear to lag the slope of the fit in Scipy's Savitzky-Golay filter?

I have a simple script that performs the Savitzky-Golay filter on a toy dataset of forex prices from yahoo finance: ...
82 views

### How is image convolution actually implemented in deep learning libraries using simple linear algebra?

As a clarifier, I want to implement cross-correlation, but the machine learning literature keeps referring to it as convolution so I will stick with it. I am trying to implement image convolution ...
1 vote
75 views

### Scaling the output of a segmentation model (UNet)

So, I have to solve an instance segmentation problem and I am thinking of implementing a UNet model based on Ronneberger et. al. 2015 paper. The problem I have is that the output size has to be ...
121 views

### ResNet output dimensions of initial convolution don’t yield in an integer

I am trying to understand the ResNet dimensions, but got stuck at the first layer. We are passing a [224x224x3] image into 64 filters with kernel size 7x7 and stride=2. According to the ResNet source ...
193 views

### when depthwise separable convolution should be preferred over normal convolution?

As a novice in the realm of deep learning, I recently learned about Depthwise Separable Convolution. I have seen some tutorials and articles about it on internet, and in all of them the author ...
1 vote
278 views

1 vote
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### Understanding, visualizing and interpreting CNN activations

I am working with the first layer of a CNN and trying to understand how to interpret the activation output. My CNN takes input from 3 channels (RBG picture) and the first layer is ...
4k views

### Understanding scipy.signal.convolve2d full convolution and backpropagation between convolutional layers

I'm learning about convolutional neural networks. The convolution operation in order to extract features that is described in literature and posts used for this is quite intuitive and easy to ...
1 vote
1k views

### What will be the input_shape of tf.keras.layers.Conv3D be for these inputs

I have many videos, and each video is made up of 37 images (there are 37 frames in the whole video). And the dimension of each image is (100, 100, 3).... So the ... 1 vote
19 views

### Finding optimal time series using convolution [closed]

we logged sensor data while milling a workpiece. At several points, the workpiece was damaged and this induced a certain sensor data time series. Due to noise and since its a real world measurement, ...
1 vote
85 views

### Trade-off between number of channels and size of convolutional filters

As far as I understand, the common practice in the modern CNN architectures is to use a smaller convolutional filters, but deeper networks with more channels. One of the reason behind this is that one ...
1 vote
51 views

### Are convolutions in deep learning associative?

Let's denote "convolution in deep learing" as "convolution-deep", and "convolution in math or signal processing" as "convolution-math". As we all know, ...
1 vote
59 views

Why is it that the formula for each element in a convolution between an image $I$ and a $k \times k$ sized kernel $K$ is  (I*K)_{ij}=\sum_{m=0}^{k-1}\sum_{n=0}^{k-1}I_{(i-m),(j-n)}K_{mn}=\sum_{m=0}^{...
118 views

### Does a Convolutional Layer in a Neural Network learn the correlation between its input signals via its kernel?

I am interested in the theory behing what a convolutional neural network learns with its convolutional operations. I think it learns (useful) kernels which measure the correlation between its input ...
252 views

### What features used by CNN model should a feature store actually store? [closed]

According to MLOPs principle, it is recommended to have a feature store. The question is in the context of doing image classification using deep learning models like convolutional neural networks ...
1 vote
27 views

### Are 3D kernels in convolutions summed over their channels?

Say for example that I have a 28x28x1 grey scale image and I will perform two consecutive convolutions. The first convolution has 2 3x3x1 filters and the second has 3 3x3x2 filters. Each convolution ...
1 vote
29 views

### Can I say that a trained neural network model with less parameters requires less resources during real world inference?

Let us imagine that we have two trained neural network models with different architectures (e.g., type of layers). The first model (a) uses 1D convolutional layers with fully-connected layers and has ...
1 vote
434 views

### Comparison of different ways of Upsampling in detection models

There are various ways to increase the resolution of tensor in (width, height) dimensions, frequently used in detection models like ...
82 views

### Should kernel size always be a prime number?

Should kernel size always be a prime number? E.g. (3,3) (5,5) (7,7). While tinkering with sklearn.preprocessing.KernelCenterer(), I noticed that I could only get it ...
1 vote
475 views

### Error after merging two Deep Learning models VGG16 and ResNet50

I have merged two different models namely VGG16 and ResNet50 and given the outputs of the two models as input to another model. I have checked the Layers graph is correct. Before merging the code was ...
1 vote
36 views

### Adapting ZFNet on 2244x224 image using a filter 7X7

I am building a model based on ZFNet in Tensorflow 2.0. I am using the Petal images dataset. The images are of size 224x244x3. So my question is when implementing the first layer (conv2d) with filter ...
1 vote
108 views

### There are 2 figures explaining transposed convolution. Which one is correct?

I have been struggling to understand transposed convolution. When I search for "transposed convolution", there are 2 figures explaining transposed convolution in which I think are not ...
46k views

### ValueError: Input 0 of layer sequential is incompatible with the layer: expected ndim=3, found ndim=4. Full shape received: [None, 25, 25, 1]

I am trying to use conv1D but getting that error. My dataset's is batched and has a shape of [None, 25, 25, 1] I am using input_shape=(25,25) I am not able to figure out what should I change so I can ...
1k views

### Can anyone recommend me a very good pre-trained model for face or head detection?

I really need to know the best pre-trained models to detect faces and/or peoples' head. Not a face recognition model, but only to classify whether an object is a person's head/face or not. I'm ...
1 vote