医学图像处理笔记(5)

Color Image Processing

Primary color: R,G, B

Tricolor image

Color specification: 

RGB format, 

HIS Format; intensity（强度）: overall brightness, Hue（色调）: expressed as an angle, Saturation（饱和度）

Color Coordinate Conversion:

HIS <=> RGB

参考博客：

http://blog.sina.com.cn/s/blog_a5b3ed560100yo26.html

Color Image Enhancement

Color Balance

1. select relatively uniform light and dark gray areas

2. compute the gray level of both areas in all three component images

3. use a linear contrast stretch on two of them matching the third

contrast and color enhancement

saturation enhancement

hue alteration - cool warm

color image restoration

1. color balance

2. convert to HIS format

3. use a median filter on the hue and saturation image to reduce the random color noise

4. use an linear filter to restore the intensity , sharpens edges and enhance detail

5. use linear point operations on all three component to ensure proper utilization  of the gray scale.

Pseudocolor

this term refers to generating a color image from a monochrome image by mapping each of the gray levels to a points in color space.

Color Image Analysis

color compensation

color spread can be modeled as a linear transformation

Color Image segmentation

RGB\HIS

Origin and Representation of 3D Image

Spatially three dimensional image

2D image have been derived from the 3D wrold by camera systems that employ a persctive projection to reduce the demensionaliyt from three to two

Optical Sectioning

Computer Tomography

X-ray

Computerized axial tomography (CT)

3D Image processing

stereometry

a technique by which one can deduce the three-dimensional shape of an object from a stereoscope image pair

stereoscopic Imaging

dual camera configuration suitable for stereoscopic imaging

stereo Matching

a technique that can be used to locate the right image pixed position that corresponds to a particular left image pixel

to obtain accurate range information, one have to do this with sub-pixed accuracy

Matching procedure

1. fit imaginary windows around a pixed having the same coordinates in another image

2. compute a measure of the agreement between the image inside the two windows

3. repeat the process as the window in the right image moves toward the right

stereoscopic image display

shaded surface display

surface reflection phenomenon

Image Geometry