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Low resolution imagegrapping

Hi all.

I am doing a project on building a radiocontrolled model submarine.

I have been thinking about incorperating a small lowresolution camera in the sub, then I found this forum and started reading on CMOS image sensors. The main problem is the transmitting up to the surface. I have developed a theory on using some ultrasonic transducers to get a data transfer speed at

320 kilo bit per second. As a result I have realised, that I must stick to a resolution about 100 x 100 and 8 bit B&W with a frame rate of about 2 frames per second. The receiving of the data is based on FFT, and therefore requires lots of calculations. I plan on using a laptop to do the FFT.

Question 1: Does anyone know of a Cmos image sensor capable of outputting 8-bit B&W images in about 100x100 (would 96 x 96 be better?) or smaler resolution. And capable of running very low fps, like 0.5 to 2 frames per sec.

Question 2: I am using PIC microcontrolers at the moment, and I am thinking about using a 16 bit PIC running 40MIPS. Would that be enough to capture a picture from a sensor like the one form question 1, or would I be loosing pixels constantly. If PIC microcontrolers are a "no go" then can anyone tell me a good way of learning and evaluating a sutable atmel microcontroler?

Hope someone might help me.

Andreas

Reply to
Cellist
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So you have worked out a possible transmission method and transmission rate. Also you have worked out how much data you want to transmit.

Alternatively you use a cheap QIF cmos sensor, grab at slowest rate possible for that device and ONLY transmit either one frame in 'n' or average a few and send the averaged frame.

Work out the data rates and possible use of hardware FIFO chip to assist your acquisition of a frame for slower transmission.

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Reply to
Paul Carpenter

First off all, thanks for the quick answer. I am new to image sensors and the related buffer chips etc. So:

B&W

resolution.

Could anyone sugest a specific chip, and where to buy one. I tried a search on google, but that didn't really give anything?

Well kind of the same, where to get one, and which one?

100 x 100 resolution and 8 bit data per pixel gives 80k bit. The PIC only got 32.7k bit, so indeed a memory chip is needed.

Hope someone might help me again. Andreas

Reply to
Cellist

Try looking for CIF resolution at Omnivision for an imager. Many of their imagers can be configured to work at less than their full resolutions.

External memory might not be needed even with the PIC, but there is wisdom in choosing the CPU *after* the requirements are understood and not before.

How long do have for this project? is it a one-off, or do you expect to produce many? These issues will affect all your decisions.

Also, be careful with how you snip - you lost the attribution (and I'm too lazy to put it back) of who said "Work out the data rates and possible..." above.

Bob

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Reply to
Bob

My question is how new?

How much design experience do you have? Is this your first college project?

First work out exactly what you need as almost anything could be suggested at this stage.

How much design are you expecting to do?

You sound as if you expect to find the exact solution, to your incomplete design.

You do know what a FIFO is?

Get more of your basic design done first, entering some proper phrases in your search engine.

CMOS image sensor will give lots of hits, but try

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FIFO should give plenty of hits

As someone else has said work out what you need to do then sort out the part you need, starting with your transmission medium and camera sensor, working towards the processor in the middle.

Personally get some form of test data transmission system tested first to prove you can reliably send data for different depths of water, types of water and other conditions.

Unless you can reliably send the data, there is no point looking at the imaging components.

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Reply to
Paul Carpenter

Tell us more about your theory, please. I assume that you are using several MHz ultrasonic carrier frequency without cooking the water.

Reply to
linnix

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If you are not concerned with having the submarine interpret the image, but merely wish to see it remotely, then consider other possibilities such as keeping the image path completely independent of the control/other telemetry path. Look at amateur radio SSTV solutions (3kHz bandwidth) and consider how you might adapt them to your application.

Reply to
larwe

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