图象处理ppt.ppt

* Introduction (2) Basic elements of digital image processing Input Storage Processor Output 摄像机 扫描仪 其他输出设备 Computer 打印输出 * Terminology (1) Image and picture: used interchangeably. Digital: related to discretization and numerical operation. Digital image: 2D rectangular array of quantized samples. Only digital images can be processed by computer. Sampled in equally spaced rectangular grid, and Quantized in equal intervals of amplitude（幅度）. Digital image processing: subject a digital image to a series of operations to obtain a desired result. * Terminology (2) Generalized images: Non-optical Higher dimensional, e.g., multi-spectral images Non-standard sampled Non-standard quantized Image processing and image analysis: Image processing: image to image Image analysis: image to data Computer graphics: computer generated pictures Computer vision: machine interpretation of scenes * Terminology (3) Digitizing: converting image from analog(模拟) to digital. Display: reverse operation of digitizing, generating a visible picture from a digital image. Screen display (volatile易变的) Hardcopy (permanent) Image recording Scanning: sequentially addressing small spots in an image (pixels). Pixel: picture cell, picture element. * Terminology (4) Sampling: measuring gray level (color) of each pixel. Quantization: Representing measured values by integer (A-D conversion). sampling quantization * Terminology (5) Global operation: applied equally throughout the image. Point operation: value of output pixel depends only on the same pixel in the input. Contrast（对比度）: magnitude of gray-level difference. Noise: additive (or multiplicative) random contamination. Gray-scale resolution: number of gray levels per measure of pixel brightness. Sampling density: number of samples per unit length. Pixel spacing: reciprocal （倒数）of sampling density. Magnification: size relation between input and output. * Continuous and Discrete Approaches We use discrete techniques to process images of a continuous