#image #hdr #merge


An implementation of HDR Radiance Estimation using Poisson Photon Noise Estimator for creating HDR image from a set of images

3 releases

0.1.2 Nov 30, 2022
0.1.1 Nov 30, 2022
0.1.0 Nov 29, 2022

#53 in Multimedia

22 downloads per month

Apache-2.0 and LGPL-2.1

195 lines


This is a rust library which implements the HDR merging algorithm for camera images taken with different exposure times (or with bracketing). It uses the algorithms described in https://www.cl.cam.ac.uk/research/rainbow/projects/noise-aware-merging/2020-ppne-mle.pdf, and uses "Poisson Photon Noise Estimator" equations to estimate final radiances at each pixel position.

Current State

The library is still in early stages of development, but aims to provide a crate that can handle all HDR merging needs. Towards that end, the following todos are the top priority:

  • Proper error handling – instead of panics, return errors that can be used by users.
  • Ability to provide exposure times and gains manually when metadata is unavailable.
  • Tone mapping algorithm implementations.
  • Improve performance.


  • image-rs: Uses DynamicImage as the output format and storage format between calculations.
  • rawloader: For supporting RAW image formats.
  • rayon: For doing point calculations in parallel.
  • kamadak-exif: For getting image's metadata, specifically eposure time and gain (ISO).


let paths = vec!["src/image1.tif", "src/image2.tif", "src/image3.tif"];
let hdr_merge = image_hdr::hdr_merge_images(paths);
let stretched = apply_histogram_stretch(&fusion);



Given the following 3 exposures:

alt "1/640s" alt "1/4000s" alt "1/80s"

Resulting unprocessed image:

alt "Merged image"

After basic processing (Levels and Contrast):

alt "Processed image"


Bug reports and pull requests welcome at https://github.com/anshap1719/image-hdr



~265K SLoC