relation between pixels and file size | Adobe Community
Images are described as having so many bits per pixel. 16 bit per pixel image: , X 2 bytes per pixel = , bytes = KB; 32 bit per pixel DON'T LEARN THESE LESSONS THE HARD WAY · THE DIFFERENCE BETWEEN A. As a rule, there are 16 bits of file size per pixel. This means that there are 8 bits per byte of file size, as 2 bits equals 1 byte. In keeping with things that are equal, . Each pixel typically consists of 8 bits (1 byte) for a Black and White (B&W) image or 24 You don't need to worry about the correspondence between image pixels and It make no difference whether the image is dpi, x mm (the.
To produce the sharpest images possible on an LCD, the user must ensure the display resolution of the computer matches the native resolution of the monitor. Resolution of telescopes[ edit ] The pixel scale used in astronomy is the angular distance between two objects on the sky that fall one pixel apart on the detector CCD or infrared chip.
The focal length is the product of the focal ratio by the diameter of the associated lens or mirror. Bits per pixel[ edit ] Main article: Color depth The number of distinct colors that can be represented by a pixel depends on the number of bits per pixel bpp.
A 1 bpp image uses 1-bit for each pixel, so each pixel can be either on or off. Each additional bit doubles the number of colors available, so a 2 bpp image can have 4 colors, and a 3 bpp image can have 8 colors: Highcolorusually meaning 16 bpp, normally has five bits for red and blue each, and six bits for green, as the human eye is more sensitive to errors in green than in the other two primary colors.Lecture 4 Pixel Relationships
For applications involving transparency, the 16 bits may be divided into five bits each of red, green, and blue, with one bit left for transparency. A bit depth allows 8 bits per component. On some systems, bit depth is available: Many display and image-acquisition systems are, for various reasons, not capable of displaying or sensing the different color channels at the same site.
Therefore, the pixel grid is divided into single-color regions that contribute to the displayed or sensed color when viewed at a distance. In some displays, such as LCD, LED, and plasma displays, these single-color regions are separately addressable elements, which have come to be known as subpixels.
When the square pixel is divided into three subpixels, each subpixel is necessarily rectangular. In display industry terminology, subpixels are often referred to as pixels,[ by whom? Most digital camera image sensors use single-color sensor regions, for example using the Bayer filter pattern, and in the camera industry these are known as pixels just like in the display industry, not subpixels.
For systems with subpixels, two different approaches can be taken: The subpixels can be ignored, with full-color pixels being treated as the smallest addressable imaging element; or The subpixels can be included in rendering calculations, which requires more analysis and processing time, but can produce apparently superior images in some cases. This latter approach, referred to as subpixel renderinguses knowledge of pixel geometry to manipulate the three colored subpixels separately, producing an increase in the apparent resolution of color displays.
While CRT displays use red-green-blue-masked phosphor areas, dictated by a mesh grid called the shadow mask, it would require a difficult calibration step to be aligned with the displayed pixel raster, and so CRTs do not currently use subpixel rendering. The concept of subpixels is related to samples. Megapixel[ edit ] Diagram of common sensor resolutions of digital cameras including megapixel values A megapixel MP is a million pixels; the term is used not only for the number of pixels in an image, but also to express the number of image sensor elements of digital cameras or the number of display elements of digital displays.
In most digital cameras, the sensor array is covered with a patterned color filter mosaic having red, green, and blue regions in the Bayer filter arrangement, so that each sensor element can record the intensity of a single primary color of light. The camera interpolates the color information of neighboring sensor elements, through a process called demosaicingto create the final image.
These sensor elements are often called "pixels", even though they only record 1 channel only red, or green, or blue of the final color image.
Thus, two of the three color channels for each sensor must be interpolated and a so-called N-megapixel camera that produces an N-megapixel image provides only one-third of the information that an image of the same size could get from a scanner. Thus, certain color contrasts may look fuzzier than others, depending on the allocation of the primary colors green has twice as many elements as red or blue in the Bayer arrangement. DxO Labs invented the Perceptual MegaPixel P-MPix to measure the sharpness that a camera produces when paired to a particular lens — as opposed to the MP a manufacturer states for a camera product which is based only on the camera's sensor.
The new P-MPix claims to be a more accurate and relevant value for photographers to consider when weighing-up camera sharpness. However, with a value of 23 MP, it still wipes-off more than one-third of the D's Using a tripod to take level multi-shots within an instance, the multiple 16MP images are then generated into a unified 64MP image.
The properties of the resized x pixel image are shown on the left. The Size numbers are the same as the New column in Resize dialog box, above.
This is the result of JPEG compression. Image and file sizes are the same. In Picture Window Pro you select the print size when you print. The Width and Height attributes are ignored. This doesn't exactly hold for Photoshop. When you try to print the original You can rescale the image using the Image Size dialog box, according to the instructions above.
You rarely need to resize it. Click on Print Options If you check Scale to Fit Media, Scale is adjusted so the image fits the page. You may need to click Page Setup Or you can leave Scale to Fit Media unchecked and manually set Scale.
A small page preview in the Print Options box helps with the setting, which will be remembered as long as the image remains open.
How many pixels to you need for a sharp print? As sharp as most printers can print; about as sharp as the eye can see at normal viewing distances.
Outstanding quality in large prints, 11x17" or A3 and larger, which tend to be viewed from greater distances. Adequate, but not optimum, for small prints. Mediocre for small prints. Remember, these numbers are actual pixels per inch on the print, not the ppi setting of the image file. When an image is sent to the printer, the image editor or printer driver resizes it to the printer's native resolution-- dpi for Epson Photo printers; dpi for HP and Canon.
No manual resizing is required. There is some controversy about how good a job image editors do particularly Photoshop. Read Qimage Print Quality Challenge to learn more. I'm pleased with the results I get from Picture Window Pro. Most digital images must be resized down for the monitor display-- for web pages or e-mail.
Many people are careful to scale the resized images to 72 dpi. I know of no web browser or viewing software that pays any attention to the dpi setting.
Most monitors actually display pixels per inch, anyway. Image file formats Several file formats are available for image storage. The primary difference between them is the type and amount of image compression.
Compression reduces the amount of storage space required by an image. For example, a x pixel bit color image 3 bytes per pixel requires 9.
There are two types of compression. Lossless compression maintains all image detail, bit-by-bit.
Relationship between pixel and bit? | Yahoo Answers
The finer the detail, the less the compression. Lossless compression is used by the PNG format. It is available, though rarely used, with the TIFF format. Lossy compression sacrifices detail in order to achieve higher compression ratios.
The amount of compression depends on the detail in the image and the quality level selected when the image is saved. In addition to the standard formats, many digital cameras have the option of storing images in RAW format-- unaltered data straight out of the image sensor. The information in RAW files replicates the mosaic pattern of the Bayer filter arrays used in most digital cameras.
RAW files do not conform to any standard; they are unique to each camera and manufacturer. They must be converted to a standard format by a RAW converter or de-mosaicing program before they can opened by an image editor. The image on the right is used as to illustrate compression. It is a bit color x pixel image 3 bytes per pixeland therefore containsbytes The compression ratio is The storage required for this image in each format is shown below in bold blue.
TIFF files identified by the.
Lossless compression is available, but not universally supported. This makes TIFF files slightly larger than the images they contain. TIFF is the format of choice for saving images intended for high quality printed output. It uses lossless compression: PNG is supported by most web browsers and image editors, but it isn't widely used-- it's undoubtedly the most underrated image file format.
Its limited color palette makes it a poor choice for high-quality photographic images, although it's often used for thumbnails. Its principal feature is lossy compression, which can result in artifacts, most notably a wavy appearance near boundaries. The loss in quality and the stored image size depends on the Quality setting used to save the image. Higher quality JPEGs are larger but have more detail and fewer artifacts.
File formats are discussed in more detail in A few scanning tips by Wayne Fulton. Irfanview is a great free utility that can read and write image files in almost any format. The dialog box is shown on the right. Image quality is still pretty good, but wavy artifacts are significantly worse and detail in the rocks is reduced.