SPRUJB3 March 2024 AM67 , AM67A , TDA4AEN-Q1 , TDA4VEN-Q1
The PCID block integrates pattern conversion (re-mosaicing), IR up-sampling and IR subtraction functionality into a single block as illustrated in Figure 7-27. The Pattern conversion and IR up-sampling block performs the task of interpolating missing pixel values, where it uses a two-stage process for re-mosaicing and IR demosaicing.
In the first step, missing green channel information in the input 4x4 RGBIR CFA (at the R, B and IR locations) is interpolated to obtain the green plane to full resolution. In the second step the missing R, B and IR values are interpolated to obtain the re-mosaiced 2x2 Bayer pattern and full resolution IR output. When interpolating the missing pixel values up-sampled green plane acts as a guide for interpolation along the local features such as edges and helps avoid the smoothening. The hardware allows user to choose between constant hue or constant color interpolation schemes along with configurable parameter values that allow precedence for preservation of particular image features during the interpolation process.
The key concerns when subtracting IR signal from the re-mosaiced Bayer pattern are that the level of IR contamination is function of DBF design, the IR contamination of the R, G and B pixels is variable, and subtraction of the IR signal from clipped/saturated pixels can lead to introduction of artifacts. The PCID module can calculates the subtraction factors for every pixel location and used by IR subtraction block for decontamination based on user defined parameters.