Visible to Intel only — GUID: qdv1700471597039
Ixiasoft
Visible to Intel only — GUID: qdv1700471597039
Ixiasoft
45.3. Unsharp Mask IP Functional Description
The IP creates an unsharp mask by first calculating an approximation to the input image luminance using the input luminance equation:
The IP then performs a low-pass Gaussian blur (low-pass filter) of .
The IP subtracts this filtered luminance from the original luminance to get the high-frequency components of the luminance.
The IP multiplies this value by the strength to obtain the sharpened luminance. The following equation shows this process.
The IP creates the final output image by calculating a ratio of , which scales the RGB components of the original image. A strength of 0 results in unity ratio.
The unsharp mask has an Avalon® memory-mapped agent interface to allow run-time control of the strength of the unsharp mask operation. Set the strength to zero for the IP to pass through the video unchanged.
You need not start the IP via the run-time interface as it starts processing video on its input as soon as it comes out of reset
Changes to the strength run-time control register take effect on the next video line.
Register Behavior
Write values to the control and debugging registers to set video field dimensions. Turn on Debug Features in the GUI so you can read back these values.
Latency
The IP latency under ideal conditions is three video lines plus an additional 34 clock cycles. This latency increases if the streaming video output experiences backpressure via its axi4s_vid_out_tready input. Backpressure increases the latency by the same amount of cycles.
The sharpening strength register setting does not change the latency.