Chapter 1. Introduction. Goals of Image Processing “One picture is worth more than a thousand...
-
Upload
letitia-cook -
Category
Documents
-
view
218 -
download
1
Transcript of Chapter 1. Introduction. Goals of Image Processing “One picture is worth more than a thousand...
Goals of Image ProcessingGoals of Image Processing
“One picture is worth more than a thousand words”
1. Improvement of pictorial information for human interpretation.
2. Processing of scene data for autonomous machine perception.
Related Areas of Image Related Areas of Image ProcessingProcessing
• Image Processing: image image
• Computer Graphics: information image
• Computer Vision: image information
1. Image Analysis
2. Image Restoration
3. Image Enhancement
4. Image Compression
Applications of Image Applications of Image ProcessingProcessing
Storage requirementStorage requirement
A MxN image with 2k gray scales
# of storage bits = M x N x k
ExampleExample
Generally, transmission is Generally, transmission is accomplished in packets consisting of accomplished in packets consisting of a start bit, a byte of information, and a a start bit, a byte of information, and a stop bit. Using this approach, how stop bit. Using this approach, how many seconds would it take to many seconds would it take to transmit a 1024x1024 image with 256 transmit a 1024x1024 image with 256 gray levels at 300 baud (bits/sec)?gray levels at 300 baud (bits/sec)?
Types of ImagesTypes of Images
Analog Image
Digital Image1. Binary Image2. Gray-scale Image3. Color Image4. Multispectral Image
Vector Image
Bitmap Image• RAW no header• RLE (Run-Length Encoding)• PGM,PPM,PNM (Portable Gray Map)• GIF (Graphics Interchange Format) no more than 256 colors• TIF (Tag Image File Format) Scanner• EPS (Encapsulated Postscript) Printer• JPEG (Joint Photographic Experts Group) Compression ratio• MPEG (Motion Picture Experts Group) Video
Image FormatsImage Formats
Perception of objectsPerception of objects
1. The spectrum (energy) of light source.
2. The spectral reflectance of the object surface.
3. The spectral sensitivity of the sensor (eye or camera).
How do we see an object?How do we see an object?
Light
Object
Eye
• Luminance Lightness Rods• Chrominance Color Cones
Human eye is more sensitive to luminance than to chrominance
Spatial & Temporal Spatial & Temporal ResolutionResolution
• Spatial resolution: 4-50 cycles per Spatial resolution: 4-50 cycles per degreedegree
• Temporal resolution: 50 cycles per Temporal resolution: 50 cycles per secondsecond
• Brightness resolution: 100 gray levelsBrightness resolution: 100 gray levels
• Color measurement: •A mixture of red, green, and blue light •Values between 0.0 (none) and 1.0 (lots)
• Color examplesRed Green Blue
White 1.0 1.0 1.0 Black 0.0 0.0 0.0 Yellow 1.0 1.0 0.0 Magenta 1.0 0.0 1.0 Cyan 1.0 1.0 0.0
RGB ModelRGB Model
YIQ ModelYIQ Model
B
G
R
Q
I
Y
311.0523.0212.0
321.0275.0596.0
114.0587.0299.0
• TV transmission digital space YCBCR
analog space YIQ (NTSC) YUV (PAL)
YUV & YCYUV & YCBBCCRR Model Model
B
G
R
YR
YB
Y
V
U
Y
10.052.061.0
45.029.015.0
11.059.030.0
)(877.0
)(493.0
B
G
R
YR
YB
Y
C
C
Y
r
b
08.042.05.0
5.033.017.0
11.059.030.0
)(713.0
)(564.0