The Real Time Correction Rasterizer (RTCR) is organized as shown in the image below. Hover over each module to see details about that module's operation.
This flow will be modified shortly to reduce latency.
The Real Time Correction Rasterizer (RTCR) relies on the assumption that the input data consists of two separate components:
How Does RTCR Use this Assumption?
RTCR rasterizes a repeating cell just once. It uses bitmap copy operations to place that cell in the image, for each cell placement.
What About the Background or Frame Data?
The background data (what we call the panel's frame) is rasterized normally. Fortunately, this data is generally sparse and has a very low complexity relative to the repeating circuits so it runs very quickly through the rasterizer.
How Does RTCR tell the repeating cells from the background?
This is done by a separate program - SFGEN. SFGEN analyzes the input data and using both the hierarchy of the input and additional pattern processing can separate out the repeating cells from the background. It then produces a new output file (in GDSII format) where this separation is encoded using a new hierarchy. SFGEN needs to be run only once. The RTCR can apply a unique correction to each panel's data based on the measurements for that panel.
Is this a Reasonable Assumption?
After examining hundreds of large PCB panels this assumption is reasonable. The only times we have found it a problem are when large boards make up the panel or a board is so large it covers the entire panel.
What if the Frame and Repeating Data Interact?
RTCR takes that possibility into account. The SFGEN program, which prepares the data for the RTCR, can detect such an interaction and will separate the interacting data from the repeating data. For example, we have processed panels where each circuit has a unique serial number; SFGEN recognized this data and removed it from the repeating master and moved it into the background data.
What If I Mix Different Circuits on a Panel?
That is fully supported. Each unique circuit will produce a bitmap master cell which is then copied into the appropriate location in the final image.
My Panel Has the Same Circuit Rotated 90 and 180 degrees. Will it Work?
Yes, we don't attempt to rotate or mirror bitmaps. Instead we make a separate master cell for each unique rotation or mirror occurrence.