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Manual # 26-0302000-00 / Revision E ImagePRO – Multi Format Image Processor
31
1:1 Sampling Overview
In order to scale an image it must first be digitized. This is the process of changing the analog graphics signals (Red,
Green, and Blue for example) into pixels stored in the ImagePRO
TM
image memory. The default mode of the
ImagePRO
TM
is to over sample the input image producing more samples than there are in the original source
material. The over sampled image is then scaled to the final output resolution.
An approach called 1:1 Sampling produces a superior image by sampling the analog video signal at exactly the same
rate as that of the original source. This allows the image to be re-constructed with reduced digitizing artifacts. This
1:1 Sampling approach requires very accurate settings and even a small sampling error causes noise on the output
image. Both the sample clock frequency and phase must be correct to obtain a properly sampled image.
ImagePRO
TM
incorporates automatic adjustments in the 1:1 Sampling mode.
1:1 Sampling Operation
NOTE:
To automatically set-up for 1:1 Pixel Sampling the input image must have non-black data with 50% gray or
brighter pixels around all four edges of the active area.
The standard Windows GUI is a good example. With an appropriate image displayed on the output Monitor, scroll to
the Auto Config menu item and press Select. In a couple of seconds, the image should return properly adjusted.
The sample clock phase can be further fine tuned by adjusting it. The functions of the menu items that are unique to
1:1 sampling operation are described below.
Auto Config
This menu item is only available when Sample Mode is 1:1 and the input is analog RGB or YPbPr. Pressing SEL to
execute this command causes the system to go through a 1:1 active area acquisition process.
NOTE:
In order for Auto Config to function correctly, the input source for the currently selected channel must have
50% gray or brighter pixels around all four edges of the active area.
Sample Phase
The adjustment range is -16 to 15. Zero is the default setting for Sample Phase.
This selection is only available when Sample Mode is 1:1 and the input is analog RGB or YPbPr. The value is initially
filled in by the Auto Config command, or set to the default. The user can then further fine-tune the image by adjusting
the sample clock phase directly.
Active Area
These menu items are only available when Sample Mode is 1:1 and the input is analog RGB or YPbPr. The values
are initially filled in by the Auto Config command, or set to defaults. The user can then adjust the active area definition
directly.
For the Horizontal entries, the unit of measure is pixels. H Total indicates the total pixel count per line. H Position sets
the offset of start of active area from H sync. H Active sets the size of the active area. H Total cannot be adjusted if
input type is DVI / SDI.
For the vertical entries, the unit of measure is lines. V Total indicates the total line count per frame. V Position sets
the offset of start of active area from V sync. V Active sets the size of the active area.
NOTE: It is recommended that the user turns on the Output Raster Box on ImagePRO™ when making active
area adjustments. The input image should be adjusted to align with all four edges of the raster box. The