Lab 2

ece480 | doering | ece labs | ece | rhit

Image Acquisition Systems

Introduction

The Imaging Systems Lab offers two means two acquire an image from external sources: page scanner, and video camera. Both techniques will be used acquire image data to serve as a basis for evaluating the two systems.

Objectives

	Learn how to acquire a video camera image
	Learn how to acquire a scanner image
	Evaluate and compare the performance of the two systems

Deliverables

One-page memo (one page of text maximum, plus additional attachments as needed). Be sure to report the following:

	The evaluation criteria that your developed
	Your evaluation results
	Your preferred image acquisition system, and why you prefer it

The memo will be due at the next lab period.

Activities

Choose subject matter for both the scanner and the video camera that would be useful to evaluate the performance of each acquisition system.
Determine a set of criteria to evaluate the image acquisition techniques based on the image data you collect. You should use the same image dimensions for all image data that you collect; 640 pixels horizontal and 480 pixels vertical is recommended. Be as quantitative as you can. For example, you may wish to consider such measures as gray level dynamic range, image noise, signal-to-noise ratio, background uniformity (if appropriate), and degree of edge blurring.
Collect your images (see page scanner instructions and video camera instructions below) and make your evaluation.

Video Camera Images

What to do:

How to do it:

Use either image-1 or image-3 SGI workstation

Start "Media Recorder"

	Open Unix shell
	Enter "mediarecorder &" (the ampersand runs the application in the background so that you can get a new prompt)

Set the output image format to SGI RGB (this is the default image format)

NOTE: Selecting TIFF format here will generate a TIFF file that is not compatible with MATLAB's TIFF reader

	Select pull-down menu "Tasks -> Image -> Custom Settings"
	Select "SGI RGB" format

Select the desired input video source (choose either S-video source or composite video source)

	Single-click the "face" icon in the lower left corner of the Media Recorder
	Select "Image from Connected Source:
	Select "S-video" or "Composite"

Record the image

Clock the red "record" button. Note how a new file name appears in the list at the upper right. The image has been saved to disk at this point. You can edit the image name by single-clicking on the filename.

Start "Media Convert" application

	Right-clock the image file
	Select "Launch Media Convert"

Save image in TIFF format

	Select output media as "Image File(s)"
	Select TIFF file format
	Adjust the output file anem as needed
	Click "Start" to perform conversion

Exit the application when finished

Select "File -> Exit"

Page Scanner Images

What to do:

How to do it:

Use any SGI workstation

Start the page scanner application

	Open a Unix shell
	Enter 'gscan'

Set the correct scanner type

Select "HP ScanJet II" scanner profile

Set the desired image type (grayscale, binary, or color)

	Select pull-down menu "Parameters"
	Select "Grey" (or other format appropriate to your needs)

Set up the application to display scan area in pixels

	Select pull-down menu "Parameters"
	Select "Scan Area"
	Check the "pixels" checkbox

Ready your source material

Place the source material face down on the scanner, with the top of the page farthest from your (look for the green page cornet symbol that indicates upper left side of the page)

Preview the source material

Press the "Prescan All" button

Set the desired "area of interest", or AOI

	Use the mouse to adjust the size and position of the red rectangular box
	Watch the indicators in the upper right to achieve the desired resolution and image size in both the X and Y directions
	Note that the total file size is also calculated as you adjust the box.

Setup the application to capture the image to a file

Select the "Scan to file" mode

Capture the image

	Press the "Scan Image" button
	Select TIFF as the filetype
	Press "OK"

Exit the application when you have created all your images

	Select "Setup"
	Select "Quit"

For questions or comments regarding this web contact:
Last updated: 03/10/05.