Automated tonal balancing

Patent metadata

Field	Value
Publication number	US-9589334-B2
Application number	US-201514708129-A
Country	US
Kind code	B2
Filing date	May 8, 2015
Priority date	May 8, 2014
Publication date	Mar 7, 2017
Grant date	Mar 7, 2017

Abstract

A system for automated tonal balancing, comprising a rectification server that groups and processes images for use in tone-matching and provides them to a tone-matching server, that then performs tone-matching operations on the images and provides them as output for review or storage, and methods for tonal balancing using the system of the invention.

First claim

What is claimed is:

1. A method for automatically generating large-scale tonally-balanced orthomosaic images, the method comprising the steps of:
receiving, at a tone-balancing server computer comprising program code stored in a memory, a plurality of orthorectified input images associated with a geographic region;
obtaining a reference image for the geographic region;
for each orthorectified input image, performing the steps of:
subdividing the orthorectified input image into a plurality of patches;
computing a pixel-level tonal mapping function for each patch to match a corresponding set of pixels of the reference image;
computing a first global tonal mapping function for each orthorectified input image by, for each pair of patches of the respective orthorectified input image, computing a function that smoothly connects the respective pixel-level tonal mapping function for the pair of patches; and
applying the first global tonal mapping function to each pixel of the each orthorectified input image to create a plurality of tonally-balanced orthorectified output image;

computing a second global tonal mapping reference by smoothly matching each first global tonal matching function for neighboring pairs of orthorectified output images; and
applying the second global tonal matching function to each pixel of each tonally-balanced orthorectified output image to create a single new, global orthorectified tonally-balanced output image of the geographic region encompassed by the plurality of orthorectified input images.

Assignees

• Digitalglobe Inc

Inventors

• Swanson Nathan Reid
• Young Patrick
• Stirling Spencer

Classifications

• G06T2207/10024

  Color image · CPC title

• G06T2207/20012

  Locally adaptive · CPC title

• G06T2207/20208

  High dynamic range [HDR] image processing · CPC title

• G06T2200/32

  involving image mosaicing · CPC title

• G06T3/4038

  Image mosaicing, e.g. composing plane images from plane sub-images · CPC title