Digital Image processing--big job,

1. What is grayscale, pixel, pixel, resolution, grayscale value.

2. What is called the straight side, what is the equilibrium, and what is the equilibrium of the straight.

Grayscale uses a black tone to indicate an object, that is, black as the reference color, different saturation of the black to display the image. Each grayscale object has a luminance value from 0% (white) to 100% (black).

A "pixel" is a unit of digital imagery that consists of the letters of the two words, the image (Foreign language: picture) and the element (Foreign language: element).

Image depth: The number of bits that are used to store each pixel

Dots are sometimes used to represent pixels, especially computer marketers, who use DPI most of the time (dots per inch). The more pixels used to represent an image, the more the result is closer to the original image. The number of pixels in an image is sometimes referred to as the resolution of the image.

In computer programming, images made of pixels are called bitmaps or raster images. The word grating is derived from analog television technology. Bitmap images can be used to encode digital imagery and some types of computer-generated art. Simply put, the pixel is the value of the point of the image, dots drawn into lines, lines drawn into the face. The sharpness of a picture is, of course, not determined by pixels.

Pixel value the pixel that the camera says is, in fact, the maximum pixel meaning, pixel is the unit of resolution, this pixel value is only the effective maximum resolution supported by the camera. 640x480 1024x768 5 "(3.5x5 inch) 6" (4x6 inch) million 1600x1200 8 "(6x8 inch) 5" (3.5x5 inch) 3,102,048 X 1536 "(8x10 inch) 7" (5x7 inch) 430 million 2400x1800 "(10x12 inch) 8" (6x8 inch) million 2560x1920 "(10x12 inch) 8" (6x8 inch) million 3000x2000 14 "(1 1x14 "(8x10 inch) million 3264x2488" (12x16 inch) "(8x10 inch) 1100 million 4080x2720" (16x20 inch) 10x12 million 1400 24 "(18 x24 inch) "(11x14 inch) above is approximately the size.

units When the picture size is in pixels, we need to specify its fixed resolution to convert the picture size to the actual size in the real world. For example, most Web page production common image resolution is 72, that is, pixels per inch is 72, 1 inches equals 2.54 centimeters. Then the conversion can be obtained per centimeter equals 28 pixels, such as 15*15 cm length of the picture, equal to the length of 420*420 pixels. DPI: dots per inch) LPI (lines per inch) PPI (pixels per inch). One

5 million pixels the number of different colors that can be expressed by pixel pixels depends on the bit per pixel (BPP). This maximum number can be obtained by taking a power of two of the color depth. For example, the common values are: 8 BPP [2^8=256; (256 colors)]; bpp [2^16=65536; (65,536 colors, referred to as high color)]; [2^24=16777216; (16,777,216 colors, called true colors)]; 48 BPP [2^48=281474976710656; (281,474,976,710,656 colors, for many professional scanners). Resolution (image resolution, Hong Kong and Taiwan translated as "resolution degree", "analytic degree", also known as "solution Force") is the precision of the screen image, refers to the display of the number of pixels.
The resolution is represented by the number of intersection points of all meridians and parallels.

Histogram is a graphical representation of the statistical characteristics of the gray-scale distribution of pixels in an image. For digital images, such as the horizontal axis of the digital image of the gray level (0-255), the ordinate represents each gray level of the number of pixels, or the proportion (normalized) formed by the statistical curve called "histogram" we can read from the histogram of the approximate description of the image, such as the gray scale of the image, gray level distribution, The average brightness of the image, the energy of the image and other important features. However, the histogram does not fully describe an image because the histogram does not contain the geometric position information of a grayscale pixel. For example, a graph is the only one that corresponds to a histogram, but a histogram can correspond to different images.
Histogram correction (equalization) is a common algorithm for gray-scale enhancement. Advantages: After equalization, the gray range of the image is expanded, the place of special brightening and the place of special darkening are enhanced, contrast is enhanced.
Cons: The image also has no original image smooth and delicate.