mat2image

Rust crate that exposes ToImage trait.

It implements ToImage for Mat to convert it into DynamicImage.

It also exposes ToImageUnsafe. The rationale behind this, comes after learning through profiling that Mat::iter is painfully slow. Then Mat::to_image_unsafe is implemented using Mat::data accessing the raw data.

Running examples

Save as

This example reads an image (examples/tinta_helada.jpg) using opencv and saves it using image API.

cargo run --release --example save_as [output_name[.jpg]=out.jpg]

Profiling

When noticing that to_image takes too much time, I profiled using perf and visualized it with Firefox Profiler.

Full profiling:

# build example with debug symbols
cargo build --example save_as

# record perf data
# sudo because of `paranoid` kernel setting
sudo perf record -g -F 999 ./target/debug/examples/save_as

# convert output to firefox readable type
sudo perf script -F +pid >save_as.perf

Then load it in Firefox Profiler.

References

• Rust profiling
• Firefox Profiler Guide

Notes

• Can we convert BGR to RGB cheaply? - Seems like it can't be done: image#1723
• cv-convert does not have implementation for Mat -> DynamicImage yet. There is an issue raised to merge this code into cv_convert.