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 (HDRI or just HDR), the goal is to capture a scene with a higher dynamic range than the camera is capable of capturing with a single exposure. [1][2]
By using different exposure parameters on the same scene, a wider dynamic range can be represented and later merged into an image with better dynamic range. After correcting for small shifts that may inadvertently happen with hand-held devices, the full-image can be fused in two ways:[3]
A higher dynamic range raw image can be reassembled and tone-mapped like usual HDR images,[4][5] or more commonly:
A blended image can be directly produced without reconstructing a higher bit-depth.[6]
The former method assumes a linear response from the camera, which may be provided by DNG or other raw formats. Some variants can take developed images, but the process of reconstructing the intensities is complicated and noisy, compromising the effective dynamic range.[5]
The latter method [Mertens-Kautz-Van Reeth (MKVr)] only cares about aligning features and taking the best parts, automatically (by contrast, saturation, and proper exposure) or manually, so it is immune to this drawback. However, it cannot be considered a true HDR technique because no HDR image is ever created. The image does look better on displays, but the resulting bit depth of the image is equal to the input depth, unlike on a true HDR image where a greater bit depth allows storing more detailed intensity changes.[1] Flexibility being its strength, this method can be extended to perform focus stacking by using contrast as the sole criteria.[7]
In photomicrographyedit
In photomicrography, the exposure fusion is often the only way to acquire properly exposed images from stereomicroscopes. One of the software solutions designed for photomicrography is the HDR module for QuickPHOTO microscopy software. This module can be also combined with Deep Focus focus stacking module to solve another problem, which is shallow depth of field of stereomicroscopes.
Related Techniquesedit
Similar imaging techniques are used in other fields. For example, in THz computational imaging, due to the weak signal of THz radiation, synchronous amplifiers coupled with a detector are used. The spatial distribution of THz radiation reflected from the object under study has large brightness differences that do not allow it to be registered by a single ADC. To solve this problem, two ADCs are connected to the synchronous amplifier, allowing two sets of data to be received simultaneously. ADCs have complementary sensitivity settings: one ADC allows measuring weak signals at the noise level on the periphery of the registration area, and information from the second ADC with the settings allows registering powerful signals is used in the central areas, where intense THz radiation reflected from the object prevails.[8]
^ abEvans, Mark (2009), Exposure Fusion: What is it? How does it Compare to HDR? How Do I Do It?, retrieved 2011-01-21
^McNeal, Kevin (2010), Exposure Fusion – Best Way To Blend Images, retrieved 2011-01-21
^Ward, Greg (6 April 2012). "Fast, Robust Image Registration for Compositing High Dynamic Range Photographs from Hand-Held Exposures" (PDF). Journal of Graphics Tools. 8 (2): 17–30. doi:10.1080/10867651.2003.10487583. S2CID 17984464.
^Luijk, Guillermo. "Zero Noise Virtual RAW". Zero Noise Photography. Retrieved 11 May 2019.
^ ab"What is HDRMerge?". HDRMerge Documentation. Retrieved 11 May 2019. HDRMerge merges raw images directly, without development. In fact, it can safely assume a linear response function of the camera.
^Mertens, Tom; Kautz, Jan; Van Reeth, Frank (2007). "Exposure Fusion". Pacific Graphics. Retrieved 2011-01-21.
^Mihal, Andrew; Spiel, Christoph. "Combining Multiple Images with Enfuse 4.2". enblend.sourceforge.net. Retrieved 11 May 2019.
^Petrov, N. V.; Perraud, J.-B.; Adrien, C; Guillet, J.-P.; Smolyanskaya, O. A.; Mounaix, P. (2020-07-20). "Terahertz phase retrieval imaging in reflection". Optics Letters. 45: 4168. doi:10.1364/OL.397935.
See alsoedit
Focus stacking, the process of merging images with different focus to create a larger depth-of-field
External linksedit
Enfuse, an open-source software for HDR fusion. Part of Hugin.
HDRMerge, an open-source application for creating an HDR RAW from many RAWs.
December 15, 2023
exposure, fusion, image, processing, computer, graphics, photography, exposure, fusion, technique, blending, multiple, exposures, same, scene, bracketing, into, single, image, high, dynamic, range, imaging, hdri, just, goal, capture, scene, with, higher, dynam. 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 HDRI or just HDR the goal is to capture a scene with a higher dynamic range than the camera is capable of capturing with a single exposure 1 2 Manual exposure fusionAutomatic exposure fusion Contents 1 Technique 1 1 In photomicrography 1 2 Related Techniques 2 Software 3 Notes 4 References 5 See also 6 External linksTechnique editBy using different exposure parameters on the same scene a wider dynamic range can be represented and later merged into an image with better dynamic range After correcting for small shifts that may inadvertently happen with hand held devices the full image can be fused in two ways 3 A higher dynamic range raw image can be reassembled and tone mapped like usual HDR images 4 5 or more commonly A blended image can be directly produced without reconstructing a higher bit depth 6 The former method assumes a linear response from the camera which may be provided by DNG or other raw formats Some variants can take developed images but the process of reconstructing the intensities is complicated and noisy compromising the effective dynamic range 5 The latter method Mertens Kautz Van Reeth MKVr only cares about aligning features and taking the best parts automatically by contrast saturation and proper exposure or manually so it is immune to this drawback However it cannot be considered a true HDR technique because no HDR image is ever created The image does look better on displays but the resulting bit depth of the image is equal to the input depth unlike on a true HDR image where a greater bit depth allows storing more detailed intensity changes 1 Flexibility being its strength this method can be extended to perform focus stacking by using contrast as the sole criteria 7 In photomicrography edit In photomicrography the exposure fusion is often the only way to acquire properly exposed images from stereomicroscopes One of the software solutions designed for photomicrography is the HDR module for QuickPHOTO microscopy software This module can be also combined with Deep Focus focus stacking module to solve another problem which is shallow depth of field of stereomicroscopes Related Techniques edit Similar imaging techniques are used in other fields For example in THz computational imaging due to the weak signal of THz radiation synchronous amplifiers coupled with a detector are used The spatial distribution of THz radiation reflected from the object under study has large brightness differences that do not allow it to be registered by a single ADC To solve this problem two ADCs are connected to the synchronous amplifier allowing two sets of data to be received simultaneously ADCs have complementary sensitivity settings one ADC allows measuring weak signals at the noise level on the periphery of the registration area and information from the second ADC with the settings allows registering powerful signals is used in the central areas where intense THz radiation reflected from the object prevails 8 Software editEnfuseNotes editReferences edit a b Evans Mark 2009 Exposure Fusion What is it How does it Compare to HDR How Do I Do It retrieved 2011 01 21 McNeal Kevin 2010 Exposure Fusion Best Way To Blend Images retrieved 2011 01 21 Ward Greg 6 April 2012 Fast Robust Image Registration for Compositing High Dynamic Range Photographs from Hand Held Exposures PDF Journal of Graphics Tools 8 2 17 30 doi 10 1080 10867651 2003 10487583 S2CID 17984464 Luijk Guillermo Zero Noise Virtual RAW Zero Noise Photography Retrieved 11 May 2019 a b What is HDRMerge HDRMerge Documentation Retrieved 11 May 2019 HDRMerge merges raw images directly without development In fact it can safely assume a linear response function of the camera Mertens Tom Kautz Jan Van Reeth Frank 2007 Exposure Fusion Pacific Graphics Retrieved 2011 01 21 Mihal Andrew Spiel Christoph Combining Multiple Images with Enfuse 4 2 enblend sourceforge net Retrieved 11 May 2019 Petrov N V Perraud J B Adrien C Guillet J P Smolyanskaya O A Mounaix P 2020 07 20 Terahertz phase retrieval imaging in reflection Optics Letters 45 4168 doi 10 1364 OL 397935 See also editFocus stacking the process of merging images with different focus to create a larger depth of fieldExternal links editEnfuse an open source software for HDR fusion Part of Hugin HDRMerge an open source application for creating an HDR RAW from many RAWs Retrieved from https en wikipedia org w index php title Exposure fusion amp oldid 1164415438, wikipedia, wiki, book, books, library,
