A RAW file contains the original image information as it comes off the sensor. No in-camera processing is applied. This will be done afterwards on your PC with special software. TIFF file only retains 8 bits per channel of information but it will take up twice the storage space because it has three 8 bit color [...]
Archive for the ‘Digital Imaging’ Category
JPEG
March 21st, 2011 
Andrei The most commonly used digital image format is JPEG. It is universally compatible with viewers browsers, and image editing software, it allows photographic images to be compressed up to 10 to 20 times compared to the uncompressed original with very little visible loss in image quality.
Interpolation
March 7th, 2011 Andrei Interpolation is an imaging method to increase or decrease the number of pixels in a digital image. Many compact cameras uses interpolation to produce a larger image than the sensor captured or to create digital zoom. Almost all image editing software support one or more methods of interpolation, the quality of the final image and [...]
Histogram
March 4th, 2011 Andrei As we’ve talked in the previous topics about sensors and pixels, each photo is composed of a number of pixels. Each of these pixels have a certain level of brightness, ranging from 0 (black) to 255 (white). A histogram is a graphical representation of these levels of brightness for the entire photo.
Gamma
March 2nd, 2011 Andrei All the pixels in a photo have certain level of brightness ranging from black to white. These values of the pixels serve as the input for the computer monitor. Due to technical limitations, CRT monitors output these values in a nonlinear way: Output = Input ^ Gamma
Dynamic Range Of Sensors
February 28th, 2011 Andrei The dynamic range of any sensor used in digital cameras is defined by the largest possible signal divided by the smallest possible signal it can generate. The largest signal represents the maximum amount of light that can be converted by the sensor into a unique digital value that represents a pixel into a photo. The [...]
Compression
February 4th, 2011 Andrei There are two ways in which digital images can be compressed: lossless and lossy. Lossless Compression Lossless compression is similar to what WinZip does. For example, if you compress a document into a ZIP file and later extract and open the document, the content will be identical to the original. No information is lost in [...]
Posted in Digital Imaging 
Tags: compression, digital image, jpeg, lossless, lossy, tiff 
No Comments »Color Spaces
February 1st, 2011 Andrei A color space (or color model) is an abstract mathematical model describing the way colours can be represented as groups of numbers, typically as three or four values or color components (e.g. RGB and CMYK are color models). The Additive RGB Colors The cells inside our eyes (called cone-shaped cells) are sensitive to red, green, [...]
Posted in Digital Imaging Tags: Adobe RGB, CMYk, color spaces, digital image, LAB, RGB No Comments »Bits
January 24th, 2011 Andrei In digital computers world bits are the smallest pieces of information that can be stored. One bit of information has a value of either “0″ or “1″. This values correspond with the two states of a switch: “on” and “off”. The electronic switches used in computers are called transistors.
Artifacts – Part 2
January 10th, 2011 Andrei In this second (and last) part we will talk about Moire, Maze Artifacts, Noise and Sharpening Halos. Moire and Maze Artifacts If a scene contains areas with repetitive detail which exceeds the resolution of the camera, a wavy moire pattern can appear. Anti-alias filters reduce or eliminate moire but also reduce image sharpness. Sometimes, moire [...]
Posted in Digital Imaging Tags: artifacts, digital image, maze, moire, noise, sharpening halo No Comments »
