High Definition explained


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It’s common to see the marketing hype of high definition television or HDTV but many wonder what is and how will it affect tv viewing.  This is a two part post to first define what hdtv, pixels and resolution is then secondly analyze how HD effects not only our entertainment but the effects of high definition on how we interpret graphical information.

In the current marketplace, adoption of high definition products is commonplace.  Video game consoles such as Playstation 3, Xbox 360, computer monitors 24” with 1920x1200 pixel resolution, 10 megapixel (10 million pixel) digital cameras, and now HD tvs and camcorders (1080p being 1920x1080 pixels) have brought a considerable increase over the SD or standard definition tvs of the previous generation which were 640 x 480, 307,200 or .3 megapixel displays.

To make sense of that this all means we must first define a single pixel which is simply a dot.  A dot alone is just a dot but if arranged in a grid or at least close together like the painting style called pointillism, our minds will interpreted the information of dots or pixels into images that we can understand.  Graphical resolution or definition as it’s marketed deals with the amount of dots or pixels in a given area.  For example reolution for printing on paper can be 300 dpi (dots per inch) and on screen 72 dpi (dots per inch) .  TV resolutions or definition standards are 480, 720, and 1080 which refer to the vertical dots/pixels per tv screen which then are 640x640 ,  1280x720, and 1920 x1080.  With moving pictures including movies , tvs and games add another layer of complexity on to this with frame rates and refresh rates.  Frame rates and refresh rates have to do with how many times in a given second the images are flashed in front of the viewer.  Multiple images in a given second allow are our minds to interpret the series of still images into animation or motion pictures.     

With all that being said it’s clear to see that there is a trend in consumer entertainment toward marketing and advanced the amount of pixels and increased definition. Some have said while viewing the latest digital blu-ray movie on a 1080p screen with 120 refresh rate has pictures so sharp and clear they begin to rival the naked eye.  Lets break this down.  This means that at 1080p you see 1920x1080, 2,073,600 or 2.0736 megapixels or millions of dots.  With a refresh rate of 120 hz you are seeing this many dots 2,073,600 multiplied by 120 times a second.  In comparison to the naked eye which naturally would see light from the sun reflected on the surface of objects at a rate which would by the suns wave lengths of the visible light spectrum.

View our next post that compares and contrasts high definition and natural visibility.