Spot the Difference Between 1080i and 1080p HD TVs
By [http://ezinearticles.com/?expert=Johnny_Hall]Johnny Hall
A full HD TV conforms to the 1080p progressive format which produces the ultimate resolution for high def televisions. It is commonly written that the 1080p format is underutilized because of the lack if media that uses it and that the 1080p format is not beneficial to smaller screens and only benefits large screens. Both facts are not entirely true.
1080 'p' and 'i' both have a resolution of 1920 by 1080 pixels / raster. This is another fact that turns another popular misconception on its head in that the progressive scanning method has a better resolution than interlaced, they are both the same. To further illustrate this point both have 1920 pixels across 1080 horizontal rows in total.
To truly understand the operational difference of the interlaced and progressive methods of scanning, their operation must be broken down relative to time.
With true or native 1080 interlaced televisions the images displayed are refreshed 60 times every second or at a rate of 60Hz. With 1080i however only alternate rows are re-sampled for each interval. That is, the odd rows and then the even rows are refreshed on successive samples, you can deduce from this that two cycles are required to refresh all rows.
Due to the alternate row method that interlaced scanning uses the images can suffer a negative effect that is called jitter, where by images that move across the screen are jagged because the lines of pixels do not match.
Where the 1080p scanning method differs when compared to interlaced is that all 1080 rows of pixels are re-sampled at the 60 Hz rate.
If 1080i format is being input how can a 1080p television improve the situation? When using a 1080p capable television to display a 1080i signal it does what is called de-interlacing.
Using this method the images input are processed and the areas that contain movement are inter-polated and the areas that lack movement are combined. To describe the result the parts of the images that contained movement and were interpolated are the only parts that contain loss of detail, the static parts are not.
This is the method that a Full HD TV uses to display 1080i formats.
Johnny Hall has a passion for many things including technology. He is a regular contributor of articles on [
http://hubpages.com/hub/Full-HD-or-HD-Ready/]Full HD TV including a recent article about [
http://hubpages.com/hub/How-to-Choose-Which-HDTV-to-Buy]LCD Full HDTV.
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