Image Subtraction
Image Subtraction - Related Videos
09:43
Measuring Reaction Time and Donders' Method of Subtraction
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2023
Source: Laboratory of Jonathan Flombaum—Johns Hopkins University The ambition of experimental psychology is to characterize the mental events that support the human ability to solve problems, perceive the world, and turn thoughts into words and sentences. But people cannot see or feel those mental events; they cannot be weighed, combined in test tubes, or grown in a dish. Wanting to study mental life, nonetheless, Franciscus Donders, a Dutch ophthalmologist in the early 1800s, came up with a...
01:22
Detection of Internal Carotid Artery Narrowing Using Digital Subtraction Angiography
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2025
Position a human patient with internal carotid stenosis, a condition characterized by narrowing of the internal carotid artery, on the imaging table for digital subtraction angiography (DSA). Insert an angiocatheter into the common carotid artery at the fourth cervical vertebra level. Capture a pre-contrast X-ray image to record background structures like bones and soft tissues using X-ray irradiation. Administer an iodine-based contrast medium into the carotid artery. The contrast medium...
09:40
Novel Sequence Discovery by Subtractive Genomics
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Cited by 8 •
2019
The purpose of this protocol is to use a combination of computational and bench research to find novel sequences that cannot be easily separated from a co-purifying sequence, which may be only partially known.
12:19
Rapid Subtractive Patterning of Live Cell Layers with a Microfluidic Probe
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Cited by 2 •
2016
We present a protocol to perform subtractive patterning of live cell monolayers on a surface. This is achieved by local and selective lysis of adherent cells using a microfluidic probe (MFP). The cell lysate retrieved from local regions can be used for downstream analysis, enabling molecular profiling studies.
08:57
Improving Infrared Spectroscopy Characterization of Soil Organic Matter with Spectral Subtractions
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Cited by 19 •
2019
SOM underlies many soil functions and processes, but its characterization by FTIR spectroscopy is often challenged by mineral interferences. The described method can increase the utility of SOM analysis by FTIR spectroscopy by subtracting mineral interferences in soil spectra using empirically obtained mineral reference spectra.
FAQs
Registration aligns the baseline and experimental frames so that corresponding pixels refer to the same anatomical or cellular locations. Without that alignment, a positional mismatch could appear as an apparent change in the resulting image. Proper registration therefore helps the subtraction emphasize altered fluorescence, morphology, or tissue structure rather than differences caused by how the images were positioned.
Stable features present in both frames contribute similarly to each pixel-wise comparison and can be reduced, while features that differ remain more visible. This can lower the visual dominance of relatively unchanged background information and make stimulus-related, disease-associated, or experimental changes easier to inspect. The result is not a replacement for the original images, but a focused view of their differences.
Within neuroscience imaging, subtraction can expose changes in fluorescence associated with neural activity, alterations in cellular morphology, and differences in tissue structure. These signals may be difficult to distinguish in either raw frame because stable visual features remain present. Comparing the difference image with the baseline and experimental images helps relate the highlighted pattern to the underlying anatomy.
First, obtain a baseline image and an experimental image from the relevant time points or conditions. Next, register the frames so corresponding features align. Then remove the reference-frame pixel value from the matching experimental pixel value to generate a difference image. Finally, examine the result alongside the source frames to identify changes in fluorescence, morphology, or tissue structure.
The baseline serves as the reference against which the experimental frame is evaluated, so it should represent the relatively stable visual state being compared. Alignment also matters because subtraction assumes that corresponding pixels describe corresponding locations. If either the reference condition or spatial correspondence is inappropriate, the difference image may emphasize unrelated variation instead of the change of interest.
It is useful when researchers need to examine changes across time or conditions while reducing shared visual information. Applications described for neuroscience include neural-activity analysis, microscopy experiments, and studies of cellular or tissue changes. The same workflow can help separate stimulus-related or disease-associated alterations from relatively stable features in time-resolved imaging data.