iridix HDR


iridix lets cameras see like the human eye.

It’s the most successful technology of its kind in the market and behind high-quality still and video captures modes in DSCs, DSLRs, smartphones and video cameras by major brands.

iridix is a local tone map engine and is the product of over a decade’s research into how the human visual system adjusts to different lighting conditions

It dynamically applies different processing to each pixel of each video frame to pull out hidden detail in shadows and highlights while preserving colors, local contrast and natural appearance.

In the image above, iridix applies pixel-by-pixel tone curve adjustment automatically to pull out detail simultaneously from shadows and highlights while leaving midtones untouched. The image on the right matches closely the real appearance of the scene.


iridix combines a set of features which make it particularly well-suited to embedded imaging applications.

  • Space-variant dynamic range compression (local tone mapping)
  • Non-linear color management
  • Natural imagery suitable for full embedding into camera pipeline
  • Still images up to 256MPixel, video to 16MP
  • Bayer-domain or RGB/YCbCr processing

The image on the right is achieved in a single exposure using a conventional DSC/smartphone camera module.


The latest versions of iridix integrate multiple-exposure HDR stitching technology and support for data formats used by native HDR sensors.

Multiple image captures are combined using motion compensation algorithms to prevent ghosting, to produce HDR images up to 20 bits per pixel.

iridix can compress dynamic range by up to 60dB to retain all HDR image content in standard 8-bit camera output while retaining natural image appearance.

Apical provides complete HDR camera subsystems based on iridix, including image pre-processing, HDR autoexposure and dynamic range compression (tone mapping).


iridix-based technology is available from Apical in a variety of formats, including:

  • Semiconductor IP cores, silicon-proven to 28nm
  • OS-independent embedded software libraries
  • OpenGL and OpenCL software libraries

All implementations of iridix are compact, low-power and support high pixel rates.