Interfacing with Webcam

happytron

in Integration and Hardware • 8 months ago

Hello,

I want to have the webcam feed images at intervals of 1 second or less, and find a particular color in that image, generate data for my micrcontroller accordingly.

Can anyone help me out interfacing the Webcam using Processing. As in is there any way to take input directly from webcam. I won't really need to save the images, just process and generate data for the micrcontroller from them.

What all would I need to learn in processing to be able to do this.

Right now I am learning the basics of image processing and setting pixels etc.

It would be great if someone could guide me on the webcam part.

Thanks.

Replies(12)

asimes

Re: Interfacing with Webcam

8 months ago

There is a library for this called OpenCV: http://ubaa.net/shared/processing/opencv/

Here is a basic setup:

import hypermedia.video.*;
OpenCV opencv;
void setup() {
size(640, 480, P2D);
opencv = new OpenCV(this);
opencv.capture(width, height);
}
void draw() {
loadPixels();
opencv.read();
set(0, 0, opencv.image());
for (int i = 0; i < width*height; i++) {
// Pixel searching code here
}
updatePixels();
}

happytron

Re: Interfacing with Webcam

8 months ago

Thanks for the reply.

Sir, I would like to ask you more about OpenCV.

Would learning about this library enable me to completely understand the code you have provided?

Also, my main goal, is image processing finding a particular color in the image taken by the webcam at periodic intervals and generate data for my arduino. Would learning OpenCV help with image processing or I would need to learn about any more additional libraries.

Really appreciate your guidance on this.

Thank you :)

asimes

Re: Interfacing with Webcam

8 months ago

Most of the code I put above can be ignored and by that I mean you don't really need to know what it is doing. Here is a general explanation:

- Load library and instantiate OpenCV:

import hypermedia.video.*;
OpenCV opencv;

- Setup OpenCV for the width and height of the sketch:

opencv = new OpenCV(this);
opencv.capture(width, height);

- Get camera information and show it:

opencv.read();
set(0, 0, opencv.image());

- This one is important! This is P2D, not OpenCV. It is what you will use to get the values of pixels into an array (built into Processing) called pixels[]:

loadPixels();

- If you make changes to pixels[] call this after:

updatePixels();

happytron

Re: Interfacing with Webcam

8 months ago

I have a few final questions left.

1. I am trying to track a color, so how exactly will be the value of pixels be stored if its in a 1-D array.

2. Will the function updatePixels(); just update a new snapshot from the webcam directly?

Thanks.

asimes

Re: Interfacing with Webcam

8 months ago

loadPixels() and updatePixels are not a part of OpenCV, they are a part of P2D, and are used when manipulating built in pixels[]. pixels[] stores 32 bit integers that represent colors. If you are not familiar with how this works check this: http://processing.org/reference/color_datatype.html

happytron

Re: Interfacing with Webcam

8 months ago

I have the latest version of processing, and I downloaded the OpenCV from the link you gave me:
http://ubaa.net/shared/processing/opencv/

From the above link I can't seem to relate to the file structure in the Processing folder.

I have a 32-bit Windows 7 installed on my laptop.

It would be nice if you could help me out a bit installing OpenCV as well. I can't really find out any clear instructions on how to do so with the latest version.

Thanks.

asimes

Re: Interfacing with Webcam

8 months ago

I actually have a Mac and have never tried to install a library to Windows. I would make a separate question for it so that people see it (this topic has just been you and I speaking).

happytron

Re: Interfacing with Webcam

8 months ago

Yes I will do that. Thanks

happytron

Re: Interfacing with Webcam

8 months ago

Sir,

Could you please help me somehow installing OpenCV with processing?

I can't find any instructions on the web, and no one is replying in the Contributed Library section.

I really want to learn :(

el_dippo

Re: Interfacing with Webcam

8 months ago

For installing a library in Processing, there is this guide.

happytron

Re: Interfacing with Webcam

8 months ago

Wow thanks...din't know Add Library tool made it so simple!!

Thanks a ton!!

happytron

Re: Interfacing with Webcam

8 months ago

How do I resolve this error??

Please help. I've tried to search about this but nothing I do fixes this.

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