COMPUTER VISION 600.461 Larry Wolff MTW 11-12 [email protected], Office: 212NEB Office Hours: Wed....

COMPUTER VISION600.461

Larry Wolff

MTW 11-12

[email protected], Office: 212NEB

Office Hours: Wed. 1-2PM

September 8, 1998 2

REQUIREMENTS• This is an introductory course on Computer

Vision.• No previous knowledge of computer vision

or image analysis is required.• Prerequisite is only that you be computer

literate:

-Know how to program in C.-Have had some exposure to UNIX

type environments.

-Able to use a Web Browser.

September 8, 1998 3

GRADING

• Midterm 20%

• Final 30%

• Problem Sets and Lab Projects 50%

September 8, 1998 4

RESOURCES

• You will need an account on a workstation such as a SUN, DEC, or an SGI. Of course direct access to the JHU network is highly desireable.

• PCs running Linux may be OK. Windows could be problematic.

September 8, 1998 5

OVERVIEW

COMPUTER IMAGING

COMPUTER VISION IMAGE PROCESSING

September 8, 1998 6

September 8, 1998 7

TIME

VOLTAGE

X X

X

X

One Pixel

One Scanline

IMAGE

September 8, 1998 8

ORGANIZATION OF A 2D IMAGE

Pixel

Binary1 bit

Grey1 byte

Color3 bytes

September 8, 1998 9

BINARY IMAGE

September 8, 1998 10

GREYSCALE IMAGE


COLOR IMAGE


RED

GREEN

BLUE

yellowmagenta

cyan

red

green

SCHEMES FOR REPRESENTING COLOR

yellow

cyan

blue

magenta

INTENSITY

RGB HSL

hue

saturation


IMAGE FILE FORMATS

Why are there so many ?

JPEGtiff

gif

PPM

pgm

BMP

EPS


OTHER IMAGING MODALITIES

• Medical Imaging

• Range sensing

• Thermal IR


CATSCAN IMAGE


RANGE IMAGE


THERMAL IMAGE


THE HUMAN EYE


Raw Image Data (pixels)

Preprocessing(images, subimages)

SegmentationEdge Detection

(spectrum, edges, lines)

FeatureExtraction

Low Level

High Level

HIERARCHICAL IMAGE PYRAMID


CONTRAST ENHANCEMENT


THRESHOLDED SEGMENTATION


HOMEWORK ASSIGNMENTDue Wed. Sept. 16

• Get familiar with a really useful image display tool called ‘XV’

• Works on popular ‘Command Line’ environments such as UNIX and on DECs and SGIs.

• If you don’t already have this you can ftp from ftp://ftp.cis.upenn.edu/pub/xv


HOMEWORK ASSIGNMENTDue Wed. Sept. 16

• Access image files by logging into cs.jhu.edu via anonymous ftp

• Display the image trees.gif and enhance contrast using ‘intensity correction’.

• Try to segment trees.gif into a binary image using ‘intensity correction’.

• Display desert.gif and modify individual RGB color bands.

COMPUTER VISION 600.461 Larry Wolff MTW 11-12 [email protected], Office: 212NEB Office Hours: Wed....

Documents

Transcript of COMPUTER VISION 600.461 Larry Wolff MTW 11-12 [email protected], Office: 212NEB Office Hours: Wed....