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Similar to sampling and Quantization in digitization
sampling and Quantization in digitization
- 2. • The sensorsproduce an image in the form of an analog signal, which is then digitized to produce a digital image. • A digital image is a two-dimensional f(x,y) function where and indicate the position in an image. • The function holds a discrete value called the intensity value. • Let’s see an example of the visual representation of spatial coordinates and amplitude of a digital image: • The digital image contains a collection of elements called pixel or picture elements, each having its intensity value. In order to enhance an image and use it for some applications, we apply various operations that are part of the image processing method. • Sampling and quantization operations are part of the image processing method that converts continuous voltage signals obtained from sensors into digital images.
- 4. • Digital imagesare basically of three types: monochrome or binary images, grayscale images, and color images. • The pixel value of a binary image at a specific location (x,y) usually holds the value 0 for black or 1 for white. • Grayscale images have intensity values ranging from 0 to 255, where 0 is black, gradually fading to 255, which is white. • Additionally, color images like RGB images contain three channels red, green, and blue channels. Each channel in an RGB image has intensity values ranging from 0-255.
- 5. Let’s see howeach image looks with the help of 4×4 samples from binary, grayscale, and RGB image: Sampling and quantization result in a matrix of rows and columns consisting of real numbers. Further, let’s say a photo is 250 x 350. Here, the width is 250, and the image height is 350. This implies that the digital image has 250 columns and 350 rows, respectively.
- 12. • Multispectral imagestypically contain information outside the normal human perceptual range. This may include IR, UV, X-ray, acoustic or radar data. • These are not image in the usual sense because the information represented is not directly visible by the human system. • However the information is often represented in visual form by mapping the different spectral bands to RGB components.
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- 39. • The samplingrate determines the spatial resolution of the digitized image, while the quantization level determines the number of grey levels in the digitized image. • A magnitude of the sampled image is expressed as a digital value in image processing. • The transition between continuous values of the image function and its digital equivalent is called quantization.
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- 41. • Spatial Resolutionin Digital Images • Spatial resolution is a term that refers to the number of pixels utilized in construction of a digital image. Images having higher spatial resolution are composed with a greater number of pixels than those of lower spatial resolution.
- 42. • Spatial resolutionand Resolution intensity are terms used in image resolution or clarity of image. • In simple terms, images are referred to as blurred or sharp, depending on the intensity of resolution. • Intensity of resolution means the number of pixels per square inch, which determines the clarity or sharpness of an image. • Spatial resolution refers to the number of pixels used in making an image. • Images with a higher number of pixels per square inch are sharp and hence said to have a higher Spatial resolution. Such images are very clear.