Skip to content Skip to navigation

OpenStax-CNX

You are here: Home » Content » Exploring High Dynamic Range Imaging: §1 Introduction to HDRI

Navigation

Lenses

What is a lens?

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

This content is ...

Affiliated with (What does "Affiliated with" mean?)

This content is either by members of the organizations listed or about topics related to the organizations listed. Click each link to see a list of all content affiliated with the organization.
  • Rice University ELEC 301 Projects

    This module is included inLens: Rice University ELEC 301 Project Lens
    By: Rice University ELEC 301As a part of collection: "ELEC 301 Projects Fall 2006"

    Click the "Rice University ELEC 301 Projects" link to see all content affiliated with them.

  • Rice Digital Scholarship

    This module is included in aLens by: Digital Scholarship at Rice UniversityAs a part of collection: "ELEC 301 Projects Fall 2006"

    Click the "Rice Digital Scholarship" link to see all content affiliated with them.

Also in these lenses

  • Lens for Engineering

    This module is included inLens: Lens for Engineering
    By: Sidney BurrusAs a part of collection: "ELEC 301 Projects Fall 2006"

    Click the "Lens for Engineering" link to see all content selected in this lens.

Recently Viewed

This feature requires Javascript to be enabled.
 

Exploring High Dynamic Range Imaging: §1 Introduction to HDRI

Module by: Tianhe Yang, Taylor Johnson, Robert Ortman, Sarah McGee. E-mail the authors

The advent of digital photography has been marked by numerous and significant technical gains in terms of resolution, noise, and convenience in post processing. However, one area in which digital media still trails its analogue counterpart is dynamic range. A capturing media’s dynamic range is its ability to maintain a wide range of information, from dark to bright values; traditional silver halide camera film excels in its ability to capture a wide range of brightness levels over even that of the priciest digital cameras.

Almost anyone with photography experience may have noticed that, in certain conditions, something they had intended to capture was either too bright or too dark to see clearly in the actual print, often becoming completely white or black and devoid of any useful information. To propose a couple of scenarios in which this phenomenon may occur: One may imagine himself taking a picture of a subject adorned with jewelry on a sunny day; while the camera meters for the subject’s face, the luster of the silver necklace may cause it adopt a white glow against the skin of the subject, particularly if the subject has darker skin (since the camera “thinks” that the average brightness is lower than you or I would perceive it to be). Likewise, taking a picture of a subject with a sunset in the background may cause the subject to lose any three-dimensionality and become a silhouette. The capturing media, in these cases, cannot cope with the extreme contrast of the scene, which, in real-life cases, may often exceed a 50,000:1ratio.

Traditionally, this problem was dealt with in the darkroom by techniques such as dodging and burning. Although image editing software such as Adobe’s Photoshop offer similar tools, the limited color depth of 8-bit file formats and even proprietary 12-bit RAW formats constrains their efficacy. Along with the myriad performance gains of digital photography in most other technical areas over traditional media and the relative ease in processing of digital images, there has been great impetus to increase the amount of captured information digitally. This is usually done by taking several images at different exposure levels and then combining them to form a high color depth result, usually 32-bits. However, a major problem surfaces with this approach; with a few exceptions, current technology in display technology, printing devices and print media simply cannot handle 32-bit files, severely limiting the usefulness of these formats. One solution is to compress the high color-depth file to one with lower color depth, such as an 8 bit JPEG or TIFF format, while maintaining the visual perception of increased color depth. In other words, one may attempt to map the extreme highlight and shadow detail present in the high color depth image into one with lower depth. This type of transformation is often termed “tone mapping”, and the conversion of multiple images into a high color depth image and “tone mapping” forms the two major bodies of “high dynamic range” imaging (HDRI).

Content actions

Download module as:

Add module to:

My Favorites (?)

'My Favorites' is a special kind of lens which you can use to bookmark modules and collections. 'My Favorites' can only be seen by you, and collections saved in 'My Favorites' can remember the last module you were on. You need an account to use 'My Favorites'.

| A lens I own (?)

Definition of a lens

Lenses

A lens is a custom view of the content in the repository. You can think of it as a fancy kind of list that will let you see content through the eyes of organizations and people you trust.

What is in a lens?

Lens makers point to materials (modules and collections), creating a guide that includes their own comments and descriptive tags about the content.

Who can create a lens?

Any individual member, a community, or a respected organization.

What are tags? tag icon

Tags are descriptors added by lens makers to help label content, attaching a vocabulary that is meaningful in the context of the lens.

| External bookmarks