Efficient holographic solutions for vehicle head-up displays

Automotive AR head‑up display with new holography method for smart windshields of the future

SPIE--International Society for Optics and Photonics

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image: 

Future smart windshield (left) displays multiplane information. A prototype (right) successfully projects holographic driving information that aligns perfectly with real-world reference objects, such as a traffic cone and a construction worker positioned at different depths, creating a seamless mix of virtual and physical reality.

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Credit: X. Sheng et al., doi 10.1117/1.APN.5.1.016005

Imagine driving down a busy highway. You need to check your speed and navigation, but glancing down at the dashboard takes your eyes off the road for a critical second. This is where head-up displays (HUDs) come in, projecting information directly onto the windshield. However, current HUD technologies are often bulky and limited to displaying flat, 2D images at a fixed distance, forcing your eyes to constantly refocus between the data and the road.

To address these limitations, a research team led by Professor Qingqing Cheng from the University of Shanghai for Science and Technology and Professor Kun Huang from the University of Science and Technology of China has proposed a new holographic display approach. Their report is published in Advanced Photonics Nexus.

The Challenge: Breaking the Digital Limits

A long-standing challenge in the field is achieving high-quality holographic imaging—using light diffraction to create virtual objects that appear to sit at different depths in the real world (e.g., navigation arrows that seem to lie directly on the pavement). However, calculating these holograms is traditionally computationally expensive.

Conventional methods, typically based on the fast Fourier transform (FFT), are rigid. They generally require the digital image source and the projected image to have matched sampling densities. When scientists try to project a small image (from a display chip) to a large area (the windshield), traditional mathematics requires adding a massive amount of "zero-padding"—essentially empty data—to make the calculation work. This wastes computer memory and slows down the process, making it impractical for real-time vehicle use.

The Solution: "Zoom Lens" for Calculations

The researchers introduced a novel calculation approach: the matrix multiplication (MM) based diffraction method. Instead of using the rigid FFT framework, they restructured the Fresnel integral into a series of flexible matrix operations.

Think of this as a "zoom lens" for calculations. The MM method allows the computer to calculate the hologram for the display chip and the windshield independently. It eliminates the need for zero-padding, effectively removing the redundant computation. In their benchmarks, this method reduced calculation time by approximately 58 percent and significantly lowered memory usage compared to traditional methods.

To validate this approach, the team built a prototype HUD system using the new algorithm. They successfully projected three different virtual images simultaneously at three distinct distances: 0.1 meters, 0.5 meters, and 1.5 meters. In their demonstration, holographic driving information was projected to align perfectly with real-world reference objects such as a traffic cone and a construction worker positioned at different depths, creating a seamless mix of virtual and physical reality.

Crucially, this method can handle extreme size differences—projecting a tiny image and a massive image at the same time—and works for both near-field and far-field displays within a single computational framework.

This technology represents a significant step toward compact, wide-field-of-view AR-HUDs. By making the computational process faster and more flexible, it opens the door for intelligent vehicles that can overlay vital safety alerts directly onto the physical environment without bulky hardware. As the team continues to refine the color and refresh rates, the smart windshield of the future is coming clearly into focus.

For details, see the original Gold Open Access article by X. Sheng et al., “Cross-scale multiplane holograms with decoupled input–output sampling for vehicle display,” Adv. Photon. Nexus 5(1) 016005 (2025), doi: 10.1117/1.APN.5.1.016005

 

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Journal

Advanced Photonics Nexus

DOI

10.1117/1.APN.5.1.016005 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Cross-scale multiplane holograms with decoupled input–output sampling for vehicle display

 

Pocketbook realities reshape Americans’ commitment to democratic ideals

New Northwestern University research finds economic insecurity weakens Americans’ commitment to core democratic norms

Northwestern University

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• Advanced behavioral experiment involved more than 600 U.S. residents  

• What voters say about democracy does not reliably predict what they actually choose when forced to decide between democratic ideals and financial interests 

• Trade-offs are not confined to one political party 

EVANSTON, IL --- Money talks, and new research from Northwestern University suggests it often speaks louder than an American voter’s commitment to democratic norms. The new study from the Center for Communication & Public Policy (CCPP) examined how U.S. residents conceptualize democracy and whether their support for democratic principles remains consistent when financial issues and other trade-offs are considered. Results are published in the journal Perspectives on Politics.  

Erik Nisbet, Owen L. Coon Endowed Professor of Policy Analysis & Communication and founder of CCPP, along with doctoral candidate Chloe Mortenson, used an advanced behavioral experiment involving more than 600 U.S. residents to examine how voters trade democratic principles against economic security. They found that support for democratic principles is far more conditional than traditional surveys suggest and declines substantially when economic hardship is taken into account. 

“Traditional surveys typically ask people whether they support democracy or value free expression,” Nisbet explains. “Decades of research show that Americans overwhelmingly say ‘yes,’ but these self-reported attitudes often do not predict actual political behavior.” 

Instead of relying on abstract poll questions, Nisbet and Mortenson employed a conjoint design, a method increasingly used in political science that reveals real-world preferences by forcing participants to make explicit trade-offs among competing values.  

“The results offer a more accurate picture of how Americans actually weigh democratic norms when faced with economic pressure,” Nisbet said. “This helps explain why ‘democracy is on the ballot’ messaging employed by Democrats underperformed in the 2024 election.” 

How the study worked 

Participants were presented with pairs of hypothetical countries and asked which democracy they would prefer to live in. Each country profile varied across four core dimensions of democratic governance: 

• Rule of law 
• Political equality 
• Freedom of expression 
• Economic well-being 

For each dimension, respondents were shown either a normative democratic condition (such as equal treatment under the law) or an illiberal alternative (such as courts favoring people like the respondent). Participants made multiple forced choices, requiring them to prioritize specific values over others –– mirroring the complex trade-offs voters might face in real political decision-making. 

Key findings 

1. Economic insecurity undermines democratic support. 
Across the sample, respondents strongly preferred democratic norms when personal economic conditions were good. Under economic insecurity, support for rule of law, political equality and free expression declined markedly across all three dimensions, with economic conditions exerting a larger influence than ideology.  

2. What Americans say about democracy doesn’t match what they choose. 
Respondents who professed strong support for democracy were often willing to abandon those principles when faced with economic disadvantages. 

3. Economic well-being is the strongest driver of democratic trade-offs. 
When respondents were financially secure, support for liberal democratic principles increased. When respondents were economically disadvantaged, they became more tolerant of illiberal conditions, including biased media, weakened checks on leaders and unequal treatment under the law. 

4. Age and education, not ideology, predict democratic resilience. 
The study found that age and education were far stronger predictors of commitment to democratic norms than political ideology. Ideology played a surprisingly minor role in determining willingness to sacrifice democratic principles –– suggesting that these trade-offs are not confined to one political party. 

Nisbet said the study’s findings suggest that responses from traditional surveys alone provide an incomplete, often misleading picture of a voter's commitment to democratic norms. 

Implications for the 2026 midterms and the 2028 presidential election 

“The research suggests that messaging focused solely on abstract democratic ideals is unlikely to resonate with voters unless it is tied to their economic concerns,” Nisbet said. “While a small segment of voters responds to moral and egalitarian appeals, broader electorates require democracy narratives grounded in pocketbook realities.”  

Nisbet says this disconnect hurt democratic messaging in the 2024 U.S. election cycle and warns Democrats against repeating the mistake in 2026 and 2028. 

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Journal

Perspectives on Politics

DOI

10.1017/S1537592725104052 

Method of Research

Survey

Subject of Research

People

Article Title

Benefit Seekers or Principle Holders? Experimental Evidence on Americans’ Democratic Trade-Offs

 

Creating hallucination-free, psychedelic-like molecules by shining light on life’s basic building blocks

Discovery could lead to new drugs for psychiatric disorders

University of California - Davis

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UC Davis researchers have developed a new method that uses light to transform amino acids — the building blocks of proteins — into molecules that are similar in structure to psychedelics and mimic their interaction with the brain. Like psychedelics, these molecules activate the brain’s serotonin 5-HT2A receptors, which promote cortical neuron growth, and could be candidates to treat a host of brain disorders, such as depression, substance-use disorder and PTSD. However, they don’t trigger hallmark hallucinogenic behavior in animal models. 

The research was recently published in the Journal of the American Chemical Society.  

“The question that we were trying to answer was, ‘Is there whole new class of drugs in this field that hasn’t been discovered?” said study author Joseph Beckett, a Ph.D. student working with Professor Mark Mascal, UC Davis Department of Chemistry, and an affiliate of the UC Davis Institute for Psychedelics and Neurotherapeutics (IPN). “The answer in the end was, ‘Yes.’”

The research opens the door to a streamlined and environmentally friendly drug discovery platform for new serotonin-effecting drugs that confer the benefits of psychedelics without significantly distorting perception.    

“In medicinal chemistry, it’s very typical to take an existing scaffold and make modifications that just tweak the pharmacology a little bit one way or another,” said study author Trey Brasher, also a Ph.D. student in the Mascal Lab and an affiliate of IPN. “But especially in the psychedelic field, completely new scaffolds are incredibly rare. And this is the discovery of a brand-new therapeutic scaffold.” 

Discovering a new therapeutic scaffold

The researchers created a library of potentially therapeutic molecules by coupling various amino acids with tryptamine, a metabolite of the essential amino acid tryptophan. They then irradiated these molecules with ultraviolet light to transform them into new compounds of medicinal value.  

Computer simulations were used to test the binding affinity of 100 of these compounds at the 5-HT2A receptor.

Five candidates were selected for further lab testing to determine efficacy and potency. Efficacies of the selected compounds ranged from 61% to 93%, with the latter representing a full agonist — a compound capable of producing the maximum biological response from the 5-HT2A system.    

The team labeled the full agonist in the group as D5. They expected that administering the compound to mouse models would induce head twitch responses, a hallmark of hallucinogenic-like behaviors. 

However, that wasn’t the case. Despite fully activating the same receptor as psychedelics, D5 didn’t induce head twitch responses.     

“Laboratory and computational studies showed that these molecules can partially or fully activate serotonin signaling pathways linked to both brain plasticity and hallucinations, while experiments in mice demonstrated suppression of psychedelic-like responses rather than their induction,” Beckett and Brasher said. 

Next steps: why no hallucinations? 

The team plans to conduct follow-up studies to better understand if other serotonin receptors in the brain modulate or suppress the hallucinogenic-like effects of D5. 

“We determined that the scaffold itself possesses a range of activity,” Brasher said. “But now it’s about elucidating that activity and understanding why D5 and similar molecules are non-hallucinogenic when they’re full agonists.” 

Additional authors on the paper include Mark Mascal and Lena E. H. Svanholm, of UC Davis; Marc Bazin, Ryan Buzdygon and Steve Nguyen, of HepatoChem Inc.; John D. McCorvy, Allison A. Clark and Serena S. Schalk, of the Medical College of Wisconsin; and Adam L. Halberstadt and Bruna Cuccurazza, of UC San Diego. 

The research reported on here was funded by grants from the National Institutes of Health and Source Research Foundation. 

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Journal

Journal of the American Chemical Society

DOI

10.1021/jacs.5c19817 

Method of Research

Experimental study

Subject of Research

Not applicable

Article Title

Transforming Amino Acids into Serotonin 5-HT2A Receptor Ligands Using Photochemistry

 

US Dietary Guidelines are a mixed bag, show industry influence, says physicians group

Physicians Committee for Responsible Medicine

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WASHINGTON, D.C. — The 2025-2030 Dietary Guidelines for Americans, released Jan. 7, score well for their streamlined approach, for limiting “bad” fat, for emphasizing fruits and vegetables, and for limiting alcohol, but need serious improvement in other areas, says the Physicians Committee for Responsible Medicine.

“The Guidelines are right to limit cholesterol-raising saturated (“bad”) fat,” says Neal Barnard, MD, FACC, president of the Physicians Committee for Responsible Medicine. “But they should spell out where it comes from: dairy products and meat, primarily. And here the Guidelines err in promoting meat and dairy products, which are principal drivers of cardiovascular disease, diabetes, and obesity.”  

“The Guidelines take a sledgehammer approach to processed foods, but plant-based and vitamin-fortified processed foods actually reduce the risk of birth defects, diabetes, heart disease, and cancer,” Dr. Barnard adds.

The health advocacy group, which has 17,000 doctor members, says there are several recommendations that the Guidelines got right and several that should be modified to keep Americans healthy.

The Guidelines are correct in:

Limiting saturated (“bad”) fat intake. Promoting plant-based foods, like fruits and vegetables.  Limiting alcohol. Streamlining advice and removing jargon, making recommendations easy to understand.

The Guidelines should be modified to:

Warn against animal protein, which is linked to heart disease and other chronic diseases. State that vegetarian and vegan diets provide all necessary nutrients, with a B12 supplement, and that plant-based processed foods are often fortified with essential nutrients and are a healthier option than animal products.    Warn against consuming dairy products, which are often high in saturated fat and linked to breast and prostate cancers. Eliminate confusion on saturated fat, specifying that it is in dairy products and meat and promotes heart disease and Alzheimer’s disease. Recognize that some highly processed foods are healthful. These include breakfast cereals and breads, which are fortified with folic acid, vitamin B12, and other nutrients that prevent birth defects and reduce risk of diabetes and cardiovascular disease. Recommend water as the beverage of choice instead of milk, recognizing milk’s link to prostate cancer, breast cancer, and lactose intolerance.

Meat and dairy products are the leading sources of saturated fat in the American diet. Research shows that consuming foods and beverages high in saturated fat raises LDL “bad” cholesterol levels, which increases heart disease risk. A new report in the Annals of Internal Medicine reaffirms that saturated fat raises cholesterol and increases the risk for heart disease. The American Heart Association Presidential Advisory reaffirms the strong evidence that saturated fat raises LDL cholesterol, which is a major driver of cardiovascular disease.

The new Guidelines’ increased protein recommendation is unnecessary and could be harmful if it results in eating more protein from animals.

“Americans already get enough protein,” says Dr. Barnard. “If the Guidelines are going to push for increased protein consumption, it should come from plants.”

Plant-based processed foods are associated with reduced risk of diabetes and cardiovascular disease and are often fortified with important nutrients, such as folic acid and vitamins D and B12, while animal products increase disease risk.

“The Guidelines have unjustly condemned highly processed foods and exonerated meat and dairy products,” says Dr. Barnard. “They should have done the reverse.”

A Harvard University study, for example, showed that animal-based products were associated with 44% increased risk of diabetes, while ultra-processed cereals were associated with 22% reduced risk.

Founded in 1985, the Physicians Committee for Responsible Medicine is a nonprofit organization that promotes preventive medicine, conducts clinical research, and encourages higher standards for ethics and effectiveness in education and research.