1. What image refers to?
Photo or video from digital video cameras, a variety of image monitoring system recorded electromagnetic radiation Space Telescope image acquired by the radar image of the reflected wave form, X-ray image medical use, B-mode images, CT images, MRI images, etc. .
2. how to represent the image?
Each image pixel called a basic unit PIXEL, for 3-D image called voxels VOXEL. 2D images may be used to represent a 2D matrix.
It may be used to represent a 2-D images of M rows and N columns
3. Typical image lena often used in image processing, cameraman
4. The sampling and quantizing
Discrete spatial coordinates called sampling, which determines the spatial resolution of the image. Is mainly determined by the camera image acquisition matrix size and arrangement of photoelectric units feel.
Discrete gray value is called quantization, which determines the amplitude resolution of the image. Mainly on the intensity of the electrical signal used to quantify the number of stages to decide.
Wherein the 256 gray levels can generally gives a feeling of continuous gradation, because of the relatively poor resolution luminance human visual system is less than 2% of the total brightness range.
The image quality
The image quality of judgment often rely on human observation, but there are some objective indicators.
Note: Rice University offers a standard test chart lena