Camera Module output data format

Hello Mark,

Welcome to the element14 Community, we hope you enjoy it! I will move this over to the Arduino area as it is a better fit.

Thank you,

Jamie

I think that code is more to do with continuous transfer. What I need to know that once the device has taken a photo in snapshot mode is it saved to its internal menory or transmitted straight out. If it is saved internally can it be accessed piece by piece or does the transmission happen all at once?

Hi Mark,

The (excellent) link that Paul posted transfers one line at a time as far as I understand.

It has to do this, because the Arduino Uno has <2k of data memory as I understand.

A simple video frame of even 160x120 low-resolution requires much more memory.

The code is likely reading multiple frames.

Your only practical options if you want to save to memory is to design a memory add-on to the Arduino

or better still just find an alternative processor or board with sufficient memory. Or find a camera module with

memory; they used to exist, and they saved as a JPEG image. They are not particularly interesting devices

though - better to just get a more resource-rich dev-board, e.g. Raspberry Pi, and a camera module for it.

shabaz wrote:

 

Hi Mark,

 

The (excellent) link that Paul posted transfers one line at a time as far as I understand.

It has to do this, because the Arduino Uno has <2k of data memory as I understand.

A simple video frame of even 160x120 low-resolution requires much more memory.

The code is likely reading multiple frames.

Your only practical options if you want to save to memory is to design a memory add-on to the Arduino

or better still just find an alternative processor or board with sufficient memory. Or find a camera module with

memory; they used to exist, and they saved as a JPEG image. They are not particularly interesting devices

though - better to just get a more resource-rich dev-board, e.g. Raspberry Pi, and a camera module for it.

Exactly

Ok maybe I'm just not reading/understanding the code properly. Where exactly in the code is the line being transferred. The while(1) loop is empty and I thought this is where it would happen and I don't see any interrupts. Apologies if this may seem like a silly question.

Hi Mark,

The while loop is calling a 'captureImg' function on line 151. I've not looked in detail, but it is apparent that it must be transferring line-by line (capturing just a line at a time) because of the fact that there is no memory to store an entire frame. The 'captureImg' function will be reading a line, transferring it, and then overwriting it with the next line. I don't know if it skips to the next frame, or the serial interface is fast enough to do it within a frame. I didn't read the code in any detail, and not used that camera module before either.

For similar cost (well, similar order) a Raspberry Pi and camera module will do it at video speed and higher resolution.

Mark Shabaz it correct.

I saw some of these camera "reading" methods applied in different environments. It is (maybe) ideal for applications like art installation but IMHO has not great real application due the number of seconds the loop need to manage the camera raws. There are almost two problems:

The first is that the entire system is slow to making an image is almost difficult in less than some seconds. So maybe good for an installation, some kind of image processing or image recognition but no more.

The second is - as Shabaz has pointed before - the reduced amount of memory (and in general the resources). This generates an implicit limitation conditioning any project. The first think that should be focused very clearly IMHO is what are the results that should be reached, to avoid to make a working project that for obvious reasons can't go ahead than the bare demonstration of the principle.

Enrico

I know that a 32 bit MCU or extra memory would be more suitable for storing the data but I will be just firing it straight into the pc so will not be stored in the MCU anyway. I will also be using a low data rate as I only need to photo 4-5 characters in the image, I will then run some software in the pc to recognise them. I wanted to know if it is possible to send it to the pc via UART while it is coming in in I2C and it seems to be true. The referenced code is quiet detailed and a bit fancy for what I need. If I can read in a certain amount of data and push it out before reading the next chunk that will suffice. I know its probably not the done thing but everybody loves a challenge. Thanks for the comments folks.

Sure you can connect the pc via UART / USB, depending on the kind of connection you have on pc-side.

Enrico

Excellent

Excellent