ECE Department: University of Massachusetts, Amherst ECE 354 Spring 2006 Lab 2: Capturing and Displaying Digital Image.

ECE Department: University of Massachusetts, Amherst

ECE 354Spring 2006

Lab 2: Capturing and Displaying Digital Image

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Big Picture Introduction

Capture an image using a digital camera Download image data to NIOS II serially through

the use of a UART A handshaking protocol will be used to

communicate with digital camera Display the image on a CRT monitor with the use

of a VGA controller Perform simple image processing Primarily written in C code Use a preexisting SOPC system with some slight

modifications

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Additional Hardware

ITM-C-328 Serial Color Digital Camera

Serial Connector and Cable

CRT Monitor

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Skills to learn

Integrate code with preexisting code Understanding previously written code Connect to a device that you did not design Writing a communication protocol to somebody

else’s specifications

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Steps taken to complete project

Begin by looking over ITM-C-328 camera documentation Plan out the series of events needed to communicate with

the camera Write a C program to send a simple request message and

receive a message in return Build up the program until ready to receive image data Image data should be stored in one continuous buffer in

SDRAM (example: char received[64]) Gain knowledge of how the DE2_NIOS_HOST_MOUSE_VGA

project displays an image to the CRT monitor Use that knowledge to display your image Finally have fun performing image processing

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Communicating with the camera

Communication with the camera is accomplished through a series of commands

A single command consists of 6 continuous single-byte RS-232 transmissions

A listing and description of the command set can be found in ITM-C 328_Manual.pdf

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Communicating with the camera (continued)

This is the command protocol to receive an uncompressed snapshot picture

Initial command to configure preview image size and color type

Snapshot command takes a snapshot and stores data in camera buffer

Get picture is used to transfer image data to host

Your task is to implement this in C code

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Information for C program

To write/read to/from the UART• fd = open(“/dev/uart”, O_RDWR | O_NONBLOCK, 0);• charReceived = read(fd, to, length);• write(fd, from, length);

I recommend looking over section II of the NIOS II Software Developer’s Handbook

A blocking read holds the program until the read operation completes with the length you specify

Think about why a nonblocking read is needed

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Recommended C code functions

A function to …• Establish a connection with the camera (Sync function)• Send a message to the camera• Receive and check a message from the camera• Receive image data from camera• Print bits of a byte received (debugging)• Print hex equivalent of a message received (debugging)

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A little help

Use the form on the bottom of this slide to • hold messages that will be sent to camera • hold messages to check received messages against

The message can be written to the UART in the following way: write(fd, SYNC, 6)

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Additional information

The image should be 2-bit gray scale with a resolution of 640x480

Uncompressed image I recommend starting with the smallest image

resolution and work from there

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Overview of DE2_NIOS_HOST_MOUSE_VGA project Implements a monochrome display, with a

preloaded image, where the user can draw on it with a mouse

USB mouse should be connected USB HOST port CRT monitor should be connected to the VGA port

You will integrate your code so that the project displays the image received from digital camera

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Displaying image through VGA controller

Look through VGA.h for VGA functions

Write C code similar to that shown below that calls functions from VGA.h to display each pixel

It is your job to come up with an equation to check each pixel in your receive buffer

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Image Processing

It is required that you implement two forms of image processing

Recommendations include:• Add timestamp onto image• Counter to keep track of number of pictures taken• Rotate, mirror, invert image• Simple edge detection (challenging)• Detect changes in images (challenging)

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Where does this project lead?

Next lab will be on the topic sending data over a network• Sending image between DE2 boards• Using computer networking knowledge learned from

Professor Ganz’s course• Don’t worry if you have not taken computer networking

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References

Camera documentation (ITM-C-328)• http://www.tdc.co.uk/camera/• Information and Datasheets

DE2_NIOS_HOST_MOUSE_VGA project

NIOS II Software Developer’s Handbook• http://www.altera.com/literature/lit-nio2.jsp

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Hints

You may need to slightly modify the SOPC system of the MOUSE_VGA project

Set the initial baud rate to what the camera initially wants

Attend my lab hours and ask lots of questions

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Questions and Comments