In a cps_spct object with multiple columns of CPS data, each acquired
using a different integration time, merge columns into a single column.
Usage
merge_cps(
x,
tolerance = 0.05,
verbose = getOption("photobiology.verbose", default = FALSE)
)Details
Pixels affected directly, or by neighbourhood, by clipping, should
be set to NA in each variable of CPS values, before passing the
spectrum as argument to parameter x of this function.
The merging of the CPS variables starts from the one corresponding to the
longest integration time, expected to contain the largest number of NA
values, by replacing NA values by cps values from the variable
corresponding to the next shorter integration. The procedure is repeated
until no NA remains or until no shorter integration time data are
available. The process stops when all NAs have been replaced, and,
even when available, CPS values for unnecesarilly short integration times
discarded.
When measuring daylight different exposures for HDR are taken sequentially, and if light conditions change rapidly the cps values may be inconsistent. If the mean ratio of cps values is outside plus/minus the tolerance, instead of merging, the data for the longer of the two exposures is discarded instead of merged (or spliced) with the longer exposure, in which case a message is emitted. Ratio is computed after discarding low signal pixels as these readings are affected by noise, distorting the ratio when the light source-spectrum has only narrow peaks of emission.