Step by Step Presets: Sharpness, Picture Resizing and Color

With the picture sharpness correctly set up, picture contours are crisp, clearly distinguishable and do not have ghosting or similar defects associated with them. Setting up the sharpness can be done quite simply and efficiently by observing screen fonts from the menu of external playback equipment (preferably connected through the HDMI interface). Although not purposefully designed for this task, the test picture "Overscan" has, on first inspection, all the prerequisites to enable the sharpness to be correctly setup.

The black lines on a gray background must appear precise and not show any signs of vertical or horizontal artifacts. The correct sharpness setting is achieved when the circle does not show double contouring or ghosting on any part of it, and yet the overall picture appears crisp. The simplest way to achieve this is to turn up the sharpness until shadowing occurs, and then knock it back down again just a touch. Be aware, however, that in many cases the controller does not possess the range to satisfactorily setup the set's sharpness, in which case this setting should be set to "Minimum".

An added benefit of the test picture is to illustrate overscan via the percentage-based picture trim guides appearing on it. At the picture extremity, the last 10 pixels are displayed as broad black lines, which can be viewed on those displays or projectors with overscan switched off or not existing at all. In today's HDTV world, and particularly for full HD compatible displays with 1920 x 1080 pixels, overscan prevents the picture from giving pixel perfect accuracy. The next test picture "Pixel Phase" is used to test the overscan accuracy.

Sharpness visualization using the "Overscan" test picture number 22 found in the submenu "Video Calibration" on the DVE High Definition DVD:

The original test picture with the sharpness set to "Neutral" and where the "Overscan" is deactivated.

The screen's overscan function has caused the picture to be excessively cropped.

An accentuated sharpness level produces hideous artifacts along the black lines.

High-resolution cinema pictures with screen resolutions of 1920 x 1080 pixels can be displayed on modern full HD compatible devices without any kind of overscan. Every individual pixel of the source material is mapped to the corresponding pixel on the television or projection screen. Both the horizontal and vertical pixels must align centrally on the screen. If just one horizontal or vertical line of pixels is missing on the border, then the picture has to be scaled. The scaling action inherently reduces the sharpness, and where motion is being represented the image may elicit flickering (aliasing).

Multimedia applications running on a PC utilizing the full HD resolution in 1080p format display screen fonts and the Windows Taskbar perfectly through what is known as native scaling - without overscan. The Taskbar itself is outside the "safe action" area and would be simply cut off if overscan were used. This pixel perfect positioning accuracy without overscan brings with it, however, some disadvantages.

If the picture borders are really not clean and do not have the correct picture information, as is the case for example with scaled-up standard television pictures, then these artifacts will be visible on the screen. To prevent this from happening, some TV models and projectors do allow the user to reactivate the overscan function. Some higher class precision projectors have an alternative to overscan called a "Blanking" function, which masks out the ill-formed picture borders with black and is therefore able to keep its native scaling feature.

This black and white test picture serves to verify the pixel placement accuracy, particularly of full HD compatible displays with screen resolutions of 1920 x 1080 pixels or 1280 x 720 pixels. To achieve this, two test images are displayed alternatively with a checkered pattern comprising single black and white pixels on a gray background. The tiniest deviation from the native scaling, for example with overscan activated, will cause some loss in picture information or interference patterns to appear.

Pixel placement accuracy verification using the "Pixel Phase" test picture number 25 found in the submenu "Video Calibration" on the DVE High Definition disk:

The highly magnified section of a screenshot shows just how the test picture is created from individual black and white neighboring pixels on a gray background.

If overscan is active, or the screen does not support the 1080p full HDTV screen resolution, then the individual pixels do not align causing picture details to get lost and interference patterns to appear.

Color saturation is set, in general, according to personal taste. Error introduction is therefore a pre-programmed certainty. Anyone wishing to have the correct color representation on personal home theater equipment should therefore calibrate the color saturation levels with the help of a color filter, which is shipped with the DVE High Definition DVD.

The corresponding test picture on the DVE DVD shows three color bars cyan (turquoise), magenta (lilac) and blue with a 75% saturation level. Then, when viewing through the filter, which has a 75% saturated gray background, the result should be an image where the colors have merged to form a single entity. If the color bars appear darker than the background, then the color saturation levels are too low. If the colored bars, by comparison seem lighter than the background, then the colors are too saturated and need to be set a little lower.

More professional control monitors or projectors have what is known as a "Blue Only" function giving them the ability to activate only the blue color channel. With this method, the color filter mentioned previously is redundant - and tuning is performed with nothing more than the eye.

If the saturation balance between the individual red, green and blue color channels is still incorrect, then the saturation control built into the display has insufficient bandwidth to perform the task. In which case, setting up the color saturation parameters will require a great deal of patience and experience or, even better, help from professional color measuring instruments.

Color setup visualization with the help of the "75% Bars, Gray Ref" test picture number 5 found in the "Video Calibration" section of the DVE High Definition HD DVD.

This color filter is shipped with the DVE High Definition DVD and, with the help of a suitable color bar test picture, enables semi-professional color alignment.

This is how correctly setup color saturation levels should ideally appear. The background and the colored bars merge together to form one consolidated block.

If the saturation levels are set too high, then the blue, cyan and magenta colors bleed through the blue filter and appear lighter than the background.

If the saturation levels are insufficiently adjusted, then the colored bars appear darker than the background when viewed through the filter.