CNN'S are what?

2018-01-19 20:34:25

Hi all: I have a very fundamental question on what are CNN'S actually...

I understand fully the training process as to take a bunch of images, start with random filters, convolve, activate, calculate loss, back propagate and learn weights. Fully understood....

But recently I came across this line on Slack

CNN'S can act as a frequency filter as well

for example, a blur is a low-pass filter and it can be implemented as convolution with fixed weights;

Please Explain?(Can't understand this at all)

Thanks in Advance..

I suspect this is referring to kernels that are used in image processing for a variety of tasks. Without seeing the conversation, this is my interpretation.

The idea of a kernel in image processing is that you take a grid (maybe 3x3) and apply it to all of the locations in an image. The way you apply it is by placing it at a pixel location. Then, the 9 pixels covered by the kernel are multiplied by its weights and summed. That value is placed at that

  • I suspect this is referring to kernels that are used in image processing for a variety of tasks. Without seeing the conversation, this is my interpretation.

    The idea of a kernel in image processing is that you take a grid (maybe 3x3) and apply it to all of the locations in an image. The way you apply it is by placing it at a pixel location. Then, the 9 pixels covered by the kernel are multiplied by its weights and summed. That value is placed at that pixel location in the new image. The picture below shows it nicely. Source

    You can see how this is very much like how a convolutional filter in a CNN is applied. A set of example kernels is listed on Wikipedia. These kernels perform actions such as blurring and edge detection, so if you had a filter in your CNN with those weights, it would perform the same action.

    2018-01-19 22:48:00