Functionality
Prerequisite of HDR photography are several narrow-range digital images with different exposures. Luminance HDR combines these images and calculates a high-contrast image. In order to view this image on a regular computer monitor, Luminance HDR can convert it into a displayable LDR image format using a variety of methods, such as tone mapping. Currently fifteen different tone mapping operators (algorithms) are available, each one with its tunable parameters.
Different image processing techniques can be applied to the generated HDR images, such as resizing, cropping, rotating and a number of projective transformations.
The software also provides batch processing functionality for creating HDR images and for tone mapping them in a non-interactive way. A module for copying EXIF data among sets of images is also provided.
For users who prefers the command line, a non-GUI, non-graphical interface is also available on all supported platforms.
A common problem with HDR photography is that images need to be aligned exactly. If the subject is static, this can be achieved using a tripod or a stable surface on which the camera is placed. In the case of image data that does not align exactly, an automatic alignment can be performed using a tool provided by the Hugin project. If this automation doesn't provide the desired result, the user may improve it manually.
In photography and videography, multi-exposure HDR capture is a technique that creates high dynamic range (HDR) images by taking and combining multiple exposures of the same subject matter at different exposure levels. Combining multiple images in this way results in an image with a greater dynamic range than what would be possible by taking one single image. The technique can also be used to capture video by taking and combining multiple exposures for each frame of the video. The term "HDR" is used frequently to refer to the process of creating HDR images from multiple exposures. Many smartphones have an automated HDR feature that relies on computational imaging techniques to capture and combine multiple exposures.
High-dynamic-range rendering, also known as high-dynamic-range lighting, is the rendering of computer graphics scenes by using lighting calculations done in high dynamic range (HDR). This allows preservation of details that may be lost due to limiting contrast ratios. Video games and computer-generated movies and special effects benefit from this as it creates more realistic scenes than with more simplistic lighting models.
Tone mapping is a technique used in image processing and computer graphics to map one set of colors to another to approximate the appearance of high-dynamic-range (HDR) images in a medium that has a more limited dynamic range. Print-outs, CRT or LCD monitors, and projectors all have a limited dynamic range that is inadequate to reproduce the full range of light intensities present in natural scenes. Tone mapping addresses the problem of strong contrast reduction from the scene radiance to the displayable range while preserving the image details and color appearance important to appreciate the original scene content.
An image file format is a file format for a digital image. There are many formats that can be used, such as JPEG, PNG, and GIF. Most formats up until 2022 were for storing 2D images, not 3D ones. The data stored in an image file format may be compressed or uncompressed. If the data is compressed, it may be done so using lossy compression or lossless compression. For graphic design applications, vector formats are often used. Some image file formats support transparency.
A camera raw image file contains unprocessed or minimally processed data from the image sensor of either a digital camera, a motion picture film scanner, or other image scanner. Raw files are so named because they are not yet processed, and contain large amounts of potentially redundant data. Normally, the image is processed by a raw converter, in a wide-gamut internal color space where precise adjustments can be made before conversion to a viewable file format such as JPEG or PNG for storage, printing, or further manipulation. There are dozens of raw formats in use by different manufacturers of digital image capture equipment.
Digital photography uses cameras containing arrays of electronic photodetectors interfaced to an analog-to-digital converter (ADC) to produce images focused by a lens, as opposed to an exposure on photographic film. The digitized image is stored as a computer file ready for further digital processing, viewing, electronic publishing, or digital printing. It is a form of digital imaging based on gathering visible light.
Logluv TIFF is an encoding used for storing high-dynamic-range imaging data inside a TIFF image. It was originally developed by Greg Ward for storing HDR-output of his Radiance-photonmapper at a time where storage space was a crucial factor. Its implementation in TIFF also allowed the combination with image-compression algorithms without great programming effort. As such it has to be considered a smart compromise between the imposed limitations. It is slightly related to RGBE, the most successful HDRI storage format, an earlier invention of Greg Ward.
High dynamic range (HDR), also known as wide dynamic range, extended dynamic range, or expanded dynamic range, is a dynamic range higher than usual.
Helicon Filter, also referred to as Helicon, Filter, or as HF, was a proprietary commercial and shareware photo editing software program for Microsoft Windows, similar to such programs as Adobe Photoshop and GIMP, developed and published by Helicon Soft Ltd. Unlike these other programs, Helicon Filter is designed primarily to edit and improve existing photos and not for graphics creation. Helicon Filter's interface also differs from other programs in that compact toolbars and menus containing editing tools are replaced with labeled "filter" tabs, each tab containing labeled edit options specific to a single aspect of the picture. Although some editors used to Photoshop-style programs may initially find this layout unfamiliar and unlike the standard toolbar layout, beginners and those who don't recognize the standard icons generally find this very helpful for getting through the editing process.
RawTherapee is application software for processing photographs in raw image formats, as created by many digital cameras. It comprises a subset of image editing operations specifically aimed at non-destructive post-production of raw photos and is primarily focused on improving a photographer's workflow by facilitating the handling of large numbers of images. It is notable for the advanced control it gives the user over the demosaicing and developing process. It is cross-platform, with versions for Microsoft Windows, macOS and Linux.
HDR PhotoStudio is a discontinued high dynamic range (HDR) graphics application developed by Unified Color for the Windows and macOS operating systems. In addition to being a HDR-merge application, HDR PhotoStudio offered a set of image editing operations that worked in its dynamic range, human color range (gamut), and in high precision. It also had a Color Integrity feature that enabled preserving an image's color tone during image editing operations — for example changing an image's contrast would not change its chromatic data. This problem is usually referred to as "color shift".
In image processing, computer graphics, and photography, exposure fusion is a technique for blending multiple exposures of the same scene (bracketing) into a single image. As in high dynamic range imaging, the goal is to capture a scene with a higher dynamic range than the camera is capable of capturing with a single exposure.
Adaptive scalable texture compression (ASTC) is a lossy block-based texture compression algorithm developed by Jørn Nystad et al. of ARM Ltd. and AMD.
Pixel Camera, formerly Google Camera, is a camera phone application developed by Google for the Android operating system. Development for the application began in 2011 at the Google X research incubator led by Marc Levoy, which was developing image fusion technology for Google Glass. It was publicly released for Android 4.4+ on the Google Play on April 16, 2014. It was initially supported on all devices running Android 4.4 KitKat and higher, but became only officially supported on Google Pixel devices in the following years. The app was renamed Pixel Camera in October 2023, with the launch of the Pixel 8 and Pixel 8 Pro.
Aurora HDR is photographic software developed by Skylum Software for Mac OS X and Windows. It is designed to be a powerful and simple yet fast HDR photo editing software.
ICTCP, ICtCp, or ITP is a color representation format specified in the Rec. ITU-R BT.2100 standard that is used as a part of the color image pipeline in video and digital photography systems for high dynamic range (HDR) and wide color gamut (WCG) imagery. It was developed by Dolby Laboratories from the IPT color space by Ebner and Fairchild. The format is derived from an associated RGB color space by a coordinate transformation that includes two matrix transformations and an intermediate nonlinear transfer function that is informally known as gamma pre-correction. The transformation produces three signals called I, CT, and CP. The ICTCP transformation can be used with RGB signals derived from either the perceptual quantizer (PQ) or hybrid log–gamma (HLG) nonlinearity functions, but is most commonly associated with the PQ function.
High-dynamic-range television (HDR-TV) is a technology that uses high dynamic range (HDR) to improve the quality of display signals. It is contrasted with the retroactively-named standard dynamic range (SDR). HDR changes the way the luminance and colors of videos and images are represented in the signal, and allows brighter and more detailed highlight representation, darker and more detailed shadows, and more intense colors.
EasyHDR is a High Dynamic Range (HDR) image processing software that merges differently exposed photographs into HDR radiance map and tone maps them. With a single photograph, easyHDR can be used to increase contrast and refresh colors.
JPEG XT is an image compression standard which specifies backward-compatible extensions of the base JPEG standard.
HDR10+ is a high dynamic range (HDR) video technology that adds dynamic metadata to HDR10 source files. The dynamic metadata are used to adjust and optimize each frame of the HDR video to the consumer display's capabilities in a way based on the content creator's intentions.
