get_chumbley | R Documentation |
Compute a Chumbley test score
get_chumbley(y1, y2, window, reps = 3)
window |
width of the window (in indices) to consider for matching |
reps |
number of replicates to use in the evaluation |
b1 |
vector of equi-distant toolmark values |
b2 |
vector of equi-distant toolmark values |
Chumbley, L. S., Morris, M. D., Kreiser, M. J., Fisher, C., Craft, J., Genalo, L. J., Davis, S., Faden, D. and Kidd, J. (2010), Validation of Tool Mark Comparisons Obtained Using a Quantitative, Comparative, Statistical Algorithm. Journal of Forensic Sciences, 55: 953–961. doi:10.1111/j.1556-4029.2010.01424.x
library(dplyr)
data(br411)
b1 <- get_crosscut(x = 250, bullet=br411)
b2 <- get_crosscut(x = 150, bullet = br411)
b3 <- get_crosscut(x = 10, bullet=br411)
b1.gr <- b1 %>% get_grooves(smoothfactor=30)
b2.gr <- b2 %>% get_grooves()
b3.gr <- b3 %>% get_grooves()
# check that the grooves are actually found:
b1.gr$plot
b2.gr$plot
# get signatures
b1 <- fit_loess(b1, b1.gr)$data
b2 <- fit_loess(b2, b2.gr)$data
b3 <- fit_loess(b3, b3.gr)$data
get_chumbley(b1$resid, b2$resid, window=150, reps=5)
get_chumbley(b1$resid, b2$resid, window=150, reps=5)
get_chumbley(b1$resid, b2$resid, window=50, reps=12)
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