Block Sum Filter
The Block Sum Filter sums blocks of pixels into super pixels to increase the numeric pixel capacity and signal to noise ratio in return for reducing the spatial resolution. This is similar to binning a digital sensor at the time of image acquisition except that a binned sensor includes 1 unit of readout noise per super pixel whereas block summing or averaging combines the readout noise of all pixels in the block. Usually, the combined readout noise is not a significant issue with modern low-noise sensors. Also see the related Block Average Filter.
The Block Sum Filter command opens from
the Image Window > Process >
Filters menu and 
button
on the Main Toolbar. The "immediate"
form, shown first, opens when an image or image set is displayed in
the top-most window. The general form can be used to select source
images from folders, windows, or by matching templates.
Block Sum Filter Properties
|
Profile [|>] |
Selects the parameter profile for this command and allows you to save or work with existing presets. |
|
[Select] |
Opens the Select Source Images dialog to choose images from an image window, folder, files, name template, or a Mira File List. |
|
Width |
Specifies the width in pixels of the block being summed. For example, if Width = 2 then every 2 pixels is summed in the horizontal direction. |
|
Height |
Specifies the height in pixels of the block being summed. For example, if Height = 2 then every 2 pixels is summed in the vertical direction. |
|
Promote Pixel Type |
Specifies whether the pixel type of the resulting image is promoted to a greater bit depth to hold the increased value of the summed pixels. |
Block summing combines the pixel values in each m x n block. For integer type pixels, this can result in overflowing the maximum number represented by the pixel type. For example, an unsigned 16-bit image has a maximum pixel value of 65535; hence a group of pixels with values near 40,000 would overflow when combined even as a 2x1 super-pixel. The Promote Pixel Type check box is provided to automatically increase the numeric capacity by switching to a larger pixel type such as 32-bit floating point.
Mira Pro x64 User's Guide, Copyright Ⓒ 2023 Mirametrics, Inc. All
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