Scaler ii ip core, Nearest neighbor algorithm, Scaler ii ip core -1 – Altera Video and Image Processing Suite User Manual
Page 222: Nearest neighbor algorithm -1
Scaler II IP Core
17
2015.05.04
UG-VIPSUITE
The Scaler II IP core resizes video streams, and supports nearest neighbor, bilinear, bicubic and polyphase
scaling algorithms. The Scaler II algorithms provide a simple edge-adaptive scaling and 4:2:2 sampled
video data.
You can configure the Scaler II IP core to change the input resolution using control packets. You can also
configure the IP core to change the output resolution and/or filter coefficients at run time using an
Avalon-MM slave interface.
Table 17-1: Formal definitions of the Scaling Algorithms
Algorithm
Definition
w
in
Input image width
h
in
Input image height
w
out
Output image width
h
out
Output image height
F
Function that returns an intensity value for a given point on the
input image
O
Function that returns an intensity value on the output image
Nearest Neighbor Algorithm
Nearest-neighbor algorithm is the lowest quality method, and uses the fewest resources.
If you use the nearest-neighbor algorithm, jagged edges may be visible in the output image as no blending
takes place. However, this algorithm requires no DSP blocks, and uses fewer logic elements than the other
methods.
• Scaling down requires no on-chip memory.
• Scaling up requires one line buffer of the same size as one line from the clipped input image—taking
account of the number of color planes being processed.
For example, up scaling an image which is 100 pixels wide and uses 8-bit data with 3 colors in sequence
but is clipped at 80 pixels wide, requires 8 × 3 × 80 = 1920 bits of memory. Similarly, if the 3 color planes
are in parallel, the memory requirement is still 1920 bits.
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