Choice Of Megapixels

The properties of picture and element combine to form ‘pix’. The term was first coined by Variety Magazine in 1932. It hit the headline as an abbreviation for the word pictures. The word which was first used with reference to cinema and progressed to define the art of still pictures by photojournalists. Picture element as an artististic concept came in to the lime light in the early days of television. Paul Nipkow is the father of Bildpunkt – the German term for ‘Pixels’ literally mean ‘picture point’. This became visible as a patent in 1988. Wireless World magazine is also said to have published this term in 1927
A maga pixel comprises of one million pixels – the number of pixels in an image. The term mega pixel is also used define the number of sensor elements or display elements of digital cameras and digital displays respectively. For instance a camera is said to have “3.1.megapixels” when it comes with an array of 2048 multiplied by 1536 sensor elements. The sum of these numbers comes to 3148728.

To understand pixels, it is important to know, that photosensitive electronic are used in digital cameras. These are either CCD or (charge-couple device) or CMOS or (complementary matal-oxide-semiconductor) image sensors. However these contain a huge number of single sensor elements and each of these is employed in recording a measured level of intensity. The sensor array, in most digital cameras tends to be covered with with a filter mosiac with a pattern and colour. The colours are blue, space green and red regions in the Bayer filter arrangement. This enables each sensor element to record even a single primary colour of light in its entire intensity.

Demosaicing is a process through which the camera allows the inforamation of neighbouring sensor elements to be interpolated to make the final imge. “Pixels” is the name given to these sensor elements. This is so even where they record one channel either green remove spaces,blue or red from the ultimate image. So we can suppose that a so called N- megapixel camera that creates an N- megapixel image gives only one third of the information compared to a similar sized image from a scanner. This results in certain colour combinations looking fuzzier than others. However the result depends on the allocation of primary colours for example the colour green has double as many elements as blue or red in the Bayer arrangement.

Traditional image sensors are a study in contrast with the Foveon where the X3 sensors use three layers of sensor elements to detect the intensity of green, space red and blue at each array location. This design cancels the need for de-mosaicing and goes beyond the associated image artifacts like sharp edges with blurred colours. An N-megapixel Foveon X3 sensor captures the same load of information as an N –megapixel Bayer-mosiac sensor, the difference being that the Bayer packs the information into fewer image pixels, without any interpolation.
Image composing is the successor of 2D geometry. Some imagists deny the traditional interpretation of pixel as a little geometrical square. They claim that megapixel is more like a sprite or a correct computer image. An image which has the capacity to coverage and integrate the romote and the regular.

Filed Under: Buying A Digital Camera

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