Ensuring Noise Reduction
All forms of recording whether analog or digital are extremely vulnerable to being exposed to various external sound effects and therefore in order to ensure perfect recording without such external intrusions it is necessary to employ the process of noise reduction. Noise reduction refers to the means by which noise is eliminated from a signal. In case of electronic equipments, the electrons often deflect from their original path as a result of heat and give rise to unwanted noise. Moreover, in visual images and magnetic tapes, the grain structures allow the inclusion of unwanted noise.
The premier noise reduction technique was first employed and devised by Ray Dolby in the year 1966. Analog systems are hardly in use nowadays and for digital recording techniques there are four major noise reduction processes. Single-ended hiss reduction systems like DNR allow noise reduction not only during and after the recording but also at times of live broadcasts. Single-ended pre-recording systems like Dolby HX Pro control noise reduction while the recording is on process. Single-ended surface noise reduction like CEDAR is used for the betterment and enhancement of playback quality by removing the sounds of pops and scratches. Finally the Dual-ended systems like Dolby NR are specialized procedures applied during recording and at the playback as well.
In case of images, visuals recorded in digital devices like digital cameras are also susceptible to external unwanted sounds and there are various different noise reduction processes by which it is possible to remove these sound effects. The most effective on these cases are Gaussian filters reduce noise by rolling and inserting the primary image within a mask. Moreover, it is also possible to attain noise reduction with the help of median filters and unlike Gaussian filters, they are considered to be even more efficient in preventing blurring and overlapping of images. Several software programs have also been designed for this purpose like Adobe Photoshop, PhotoImpact, GIMP, Noise Ninja etc.
