Digital image pixel size

Fig. 1. The chemotaxis of human umbilical vein endothelial cells in response to bFGF (50 ng/mL), VEGF (50ng/mL), and the chemokines IL-8 (50 nM) and RANTES (100 nM). The assay was carried out using filters with a pore size of 8 pM, and the migration assay was carried out for 6 h. The results are given as area of the digitized image of the migrated cells (pixels), using a Sony video camera and a Kontron Vidas image analysis system.

Reconstructed digital PET images are stored in the computer in the format of a matrix. The images are characterized by two quantities matrix size and pixel depth. In PET studies, the computer memory approximates the FOV as a square matrix of a definite size that can range from 64 x 64 to 512 x 512 with a total of 1,026 (1K) to 262,144 (262 K) picture elements, called pixels, respectively. The matrix size depends on the type of study and is chosen by the operator. Since the FOV is approximated to the matrix size, the pixel size is calculated by dividing the length of FOV by the number of pixels across the matrix. For example, if an image of 250 x 250 mm FOV is stored in a... 

Shaw, R. (1999). Digital Photography the Influence of CCD Pixel Size on Imaging Performance, Proceedings of IS T s 1999 PICs Conference, IS T, Springfield, VA. 

CCD detectors are the truly omnipresent devices these days. They consist of a ID or 2D array of the previously mentioned MOS or similar mini-detectors (an individual detector element is called pixel )- This is the simplest and smallest way to build a digital imaging system with sufficient spatial resolution for most of today s applications arrays of up to 2048 x 2048 pixels (each of size 10 x 10 pm ) are no longer a rare occurrence. 

Digital image consists of discrete picture elements called pixels. Associated with each pixel is a number represented as Dn (Digital number), that depicts the average radiance of a relatively small area within a scene (pixel). The size of this area determines the reproduction of details within the scene. As the pixel size is reduced, more scene details are preserved in a digital representation. The pixel has a gray scale value where 0 corresponds to black and 255 for white in between there are shades of gray [1-5]. 

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