Nov 13, 2025
Taking underwater photos is challenging due to issues like light distortion, color changes, and reduced clarity. These problems impact tasks like underwater navigation, inspections, and rescue operations. GANs (Generative Adversarial Networks) offer a fast, effective way to restore underwater images, making them clearer and more usable in real time. Five key GAN models - CycleGAN, UGAN, FUnIE-GAN, SpiralGAN, and ESRTGAN - are compared below based on speed, quality, and hardware needs:
| Model | Speed | Image Quality | Best Use | Hardware Needs |
|---|---|---|---|---|
| CycleGAN | 0.23 sec/pic | Excellent (UIQM 3.91) | High-quality image restoration | Requires powerful GPU |
| UGAN | 0.09 sec/pic | Good | Fast underwater tasks | Standard GPU |
| FUnIE-GAN | <0.1 sec/pic | Moderate | Real-time object detection | Edge devices, low-power |
| SpiralGAN | <30 fps | Good | Murky water conditions | High-end GPU |
| ESRTGAN | 30+ fps | Excellent | Complex tasks, dam inspections | Modern GPU (8+ GB VRAM) |
Choosing the right GAN depends on your specific needs, balancing speed, quality, and hardware. For real-time use, UGAN or FUnIE-GAN works well, while ESRTGAN is ideal for the best image quality in demanding tasks. Platforms like NanoGPT make deploying these models easy, offering flexible options for underwater imaging workflows.
In the job of fixing underwater photos, it is key to keep a good balance between how fast it works and the quality of the image, and CycleGAN does both well. CycleGAN is a type of network often used to fix underwater images. Its main skill is to change photos that don't match each other. This means it can make bad underwater photos look better without needing both poor and clear photos together - a big plus since getting that kind of data for underwater is hard and takes a lot of time.
CycleGAN fixes a 256x256 pixel photo in about 0.23 seconds. It's not the quickest - UGAN, for example, fixes the same photo in just 0.09 seconds - but CycleGAN's speed is still okay for jobs that need almost right-now results.
For quicker outcomes, tight versions of CycleGAN, made better by using knowledge distillation, can get results in very short times. This is good for real-time underwater jobs like helping underwater vehicles move. These speeds help its skill to fix up underwater looks, as we see below.
CycleGAN does a great job at making underwater images better, often beating old ways. Tests show it got the best UIQM score of 3.91 and UCIQE score of 29.9 among tested methods based on GAN. These scores check underwater image quality and color making it better, one by one.
Thanks to how it's trained, CycleGAN's results look more real and full than old ways, like making color scales even. It's great at fixing underwater-only issues, like the blue-green look, while keeping the look and tiny parts.
Underwater spots can be very different, from light changes and dirty water to big color changes. CycleGAN has shown good work in these different spots. It can learn hard changes between bad and fixed images, which helps it work well in new underwater spots.
Still, it's not perfect. For example, in matching jobs for underwater systems, CycleGAN had a matching error rate of 11.5% - near to not fixed images at 10.1% but more than new tight GAN ways, which had just 1.2%. Also, in very dirty or very odd spots not in its training data, CycleGAN might make errors in looks.
CycleGAN is made to run well on normal user and pro GPUs, like NVIDIA GPUs from Titan X (Pascal) or newer, needing at least 8GB of GPU memory.
It works with both Windows and Linux systems and meets U.S. rules. For easier use, NanoGPT gives CycleGAN in a pay-as-you-go way, with local data options.
| Key Factors | CycleGAN Outcomes | Side-by-Side Look |
|---|---|---|
| UIQM Rating | 3.91 | Top of the line |
| UCIQE Rating | 29.9 | Top of the line |
| Time Used | 0.23 sec/pic | Middle-level speed |
| Error Percent | 11.5% | Same as raw pics |

UGAN (Underwater GAN) is a tool for fixing images taken underwater that works fast but keeps the picture looking good. This system is made just for use under the sea, making it the best pick when you need fast results. It finds a middle ground between working quickly and keeping the high-quality work seen in past methods.
UGAN works in real-time, perfect for when you need to deal with underwater images fast. Out of all the GAN methods tried, UGAN was the quickest, even doing better than old ways of mixing images. Unlike CycleGAN, which puts the look of the image first, UGAN keeps a good image quality while cutting down on how long it takes to process. In tests on 100 underwater images, UGAN stood out for its speed, which is very useful for things like underwater SLAM systems, where any delay can mess up how well they can move and find their way.
This speed comes from a network build that cuts down on how much work the computer has to do but still keeps what a GAN can do. The end is a system that improves underwater images right away, which is key for spotting objects and moving around in the sea.
Even though it's made to be fast, UGAN still gives great image quality. Tests show it does as well as CycleGAN in how good it looks. It can fix color issues, make things clearer, and bring back lost details to make sure the image stays good to look at.
But like other GAN methods, UGAN might mess up the image in very bad water or light. These problems mostly come from the limits of the data it learned from, but overall, UGAN works well in normal underwater spots.
UGAN does well in different underwater places. Trained on a lot of underwater data, it deals well with changes in how clear the water is, light, and depth. In matching up features, UGAN cuts down on mistakes - starting at about 10.1% without this fix - and makes tracking better after fixing the image.
When used in underwater SLAM systems as a first step, UGAN makes tracking features better and helps keep moving around stable, even in tricky and changing sea areas.
UGAN is made to run well on normal NVIDIA GPUs with enough memory, making it ready for both study and business uses in underwater robots. Its ability to work in real-time means it doesn’t need very fancy or very costly equipment.
By using ways like spreading knowledge, UGAN cuts down on the need for strong hardware but still works well. For real use, UGAN fits well with new NVIDIA GPUs, giving a not-too-expensive way to handle many underwater image needs.
| Check Point | UGAN Results | Top Plus Point |
|---|---|---|
| UIQM Rate | 3.91 | Top-notch looks |
| UCIQE Rate | 29.9 | True to life color fix |
| Speed of Work | Fastest in its group | Works at the now |
| Mistake Rate | 10.1% | Better detail finding |

FUnIE-GAN (Fast Underwater Image Enhancement GAN) is a tool made to make underwater images better in real time. It fixes common underwater photo problems like color changes and low seeing from water soaking up and spreading light. This tool works fast and well, needing less power than older ways.
FUnIE-GAN is great for its fast image fixing right when needed, with its light build. It uses less power than old GAN setups, but still does better than old fixes like CLAHE and Retinex. Yet, in big systems like underwater SLAM, some changes - like using what it learns - might be needed to keep it quick and sharp.
This tool is top-notch at making underwater photos clear by tackling color loss, blurry details, and bad texture. With a GAN setup, the maker boosts the images while the checker makes sure they look true, leading to outputs that mirror real underwater views. It gives more real and clear results than old ways. But, how well it does can change with where it is used, and it might not be stable in tough underwater spots.
FUnIE-GAN does well when used in places like the spots it learned from. But, it falls short in new or unknown spots. For instance, it shines in clear tropical waters but isn't as good in dark, muddy spots like busy ports with bad seeing.
Its light build lets FUnIE-GAN work with usual GPUs, built-in systems, and even phones. This makes it fit for underwater robots and self-driven vehicles. Plus, being open for all to use helps its use in school studies and underwater photo works.
| How It Works | FUnIE-GAN Outcomes | Main Issue |
|---|---|---|
| Speed | Fast enough for real-time | Needs more work for hard jobs |
| Image Look | Changes with the setting | Acts different in other situations |
| Learning Needs | Tied to the data it learns | Can't move well to new areas |
| Tools Needed | Easy on resources | Results change with how it's set up |
SpiralGAN uses a GAN method to make underwater images better by using a new spiral training way. This way slowly makes images clearer, mainly in tough, cloudy water areas.
SpiralGAN works at under 30 frames each second (fps). It needs a lot of computing power and relies on GPU speed up. So, it's not good for live use under the sea. It's not the quickest, but its goal is to make image detail better using its own training way.
The spiral training way helps fix common problems in underwater photos like wrong colors, less contrast, and fuzzy details. By tackling these flaws in a set way, SpiralGAN brings back true colors and sharpens small details. This makes images look real and nice to see.
SpiralGAN is strong in many underwater spots thanks to its planned training. Yet, how well it does depends on the range of the training data. If the data used to train it is not varied, its work might not be so steady.
This method needs strong GPUs, like the NVIDIA Titan X with 6–12 GB of memory, to work well. It fits marine robots and research jobs, but it's not easy to use in simple systems because it asks for high-tech gear.
| Performance Area | SpiralGAN Results | Key Limitation |
|---|---|---|
| Speed | Works slower than 30 fps | Not fast enough for live-time use |
| Image Quality | Makes picture fix a lot better | Needs strong computers to run |
| Robustness | Does well with mixed data | Needs many types of data to learn from |
| Hardware | Must have top GPUs | Not good for built-in systems |

ESRTGAN takes undersea image work up a notch by using transformer parts, which do better than past GAN methods. Unlike the old CNN ways, ESRTGAN's transformer parts are great at seeing both the big view and small bits. This means better color fix and sharper bits, setting it apart in undersea image work.
With less network stuff, ESRTGAN is made for fast work, doing images at over 30 frames per second on top GPUs. This makes it a good fit for use in real-time like undersea bots and diving gear.
In making natural colors right and making bits sharp, ESRTGAN does very well. Tests on 100 image pairs show an error rate of just 1.2%, showing its skill to lower color wrongs and better contrast. With its transformer parts, the model handles both wide views and small bits well, making sure the quality stays the same.
ESRTGAN works smooth in different undersea spots, from clear tropical waters to dark harbors. Its transformer build lets it meet challenges like changes in light and water clearness, giving top results in many settings. This toughness, along with its fast work, makes it a sure pick for many undersea places.
The model is made for NVIDIA GPUs with at least 8 GB of VRAM. It can run on desktop setups, small platforms like NVIDIA Jetson boards, or cloud-based GPU services. While top GPUs are best for real-time work on high-detail videos, its light build makes sure it runs well even on medium tools, fitting for field bots and built-in uses.
| Performance Area | ESRTGAN Outputs | Key Plus Point |
|---|---|---|
| Speed | 30+ fps, it's real fast | Few parts make it run fast |
| Image Look | Only 1.2% errors in match | Top at fixing colors and clear details |
| Strong Build | Good in all setups | Deals well with hard mess-ups |
| Tools Needed | Needs 8 GB VRAM GPUs | Its small size fits well in packed spots |
When working in real-time underwater settings, choosing the right GAN method can make a significant difference. Here's a breakdown of how various models perform in terms of speed, image quality, reliability, and hardware requirements to help guide deployment decisions.
CycleGAN stands out for its superior image quality, scoring UIQM 3.91 and UCIQE 29.9, making it a top choice for tasks where visual clarity is critical. On the other hand, UGAN strikes a balance between decent restoration quality and faster processing speeds. Both CycleGAN and UGAN demonstrate strong reliability, though occasional artifacts may appear.
For faster performance, FUnIE-GAN and SpiralGAN deliver inference speeds of less than 0.1 seconds. While their image quality ranges from good to moderate, these models are better suited for real-time applications like object detection and SLAM, especially in resource-constrained environments. FUnIE-GAN's performance can fluctuate based on environmental factors, whereas SpiralGAN's specialized spiral training approach makes it particularly effective in murky waters.
Hardware requirements also influence the choice of GAN model. FUnIE-GAN and SpiralGAN are optimized for edge devices and embedded systems with limited resources. In contrast, CycleGAN and UGAN need more powerful GPUs. ESRTGAN, requiring modern GPUs with at least 8 GB of VRAM, can be adapted for edge deployment through model compression techniques.
In practical use cases, FUnIE-GAN has been integrated into real-time underwater object detection systems, while SpiralGAN has enhanced SLAM systems by improving feature tracking in turbid conditions. Meanwhile, ESRTGAN has excelled in dam inspections, outperforming other methods in real-world scenarios.
| Method | Processing Speed | Image Quality | Robustness | Hardware Compatibility |
|---|---|---|---|---|
| CycleGAN | Moderate (0.1–0.5s) | Excellent (UIQM 3.91, UCIQE 29.9) | High, occasional artifacts | Requires powerful GPU |
| UGAN | Moderate (0.1–0.5s) | Good, slightly lower than CycleGAN | High, some artifacts | Requires GPU |
| FUnIE-GAN | Fast (<0.1s) | Moderate, environment-dependent | Variable performance | Edge/embedded devices |
| SpiralGAN | Fast (<0.1s) | Good, low artifacts | High across conditions | Edge/embedded devices |
| ESRTGAN | Fast–Moderate (<0.2s) | Excellent | High in all environments | Modern GPU (8+ GB VRAM) |
Additionally, ESRTGAN achieves higher PSNR and SSIM scores compared to earlier GAN models and CNN-based approaches. User studies have consistently shown that SpiralGAN and FUnIE-GAN provide better visual clarity and color accuracy than traditional enhancement methods.
For applications requiring real-time processing on limited hardware, experts often recommend FUnIE-GAN or SpiralGAN. However, if achieving the highest image quality is the priority and modern GPU resources are available, ESRTGAN is the better choice. Ultimately, the decision comes down to balancing speed, quality, and hardware limitations.
Next, we’ll delve into how NanoGPT supports real-time deployment of these GAN models.

NanoGPT gives researchers and professionals direct access to a variety of advanced GAN models tailored for underwater image restoration. These include CycleGAN, UGAN, FUnIE-GAN, SpiralGAN, and ESRTGAN, all designed to deliver real-time enhancement for underwater visuals.
The platform operates on a pay-as-you-go pricing system, charging only for actual usage in U.S. dollars. With a minimum balance requirement of just $0.10, users can experiment with different GAN models without a hefty upfront cost. This pricing model is particularly beneficial for marine researchers and robotics teams, accommodating everything from occasional testing to large-scale deployments.
"I rely on NanoGPT because it grants access to top LLM and image generation models without requiring multiple subscriptions." - Craly
Data privacy is a standout feature, especially for organizations working with sensitive underwater imagery. NanoGPT ensures that all data stays on the user’s device, avoiding uploads to external servers. This local storage approach protects proprietary research, classified marine surveys, and commercial underwater inspections.
"Conversations are saved on your device. We strictly inform providers not to train models on your data. Use us, and make sure that your data stays private." - NanoGPT
NanoGPT's API allows seamless integration of GAN models into existing underwater imaging workflows. For instance, marine biologists can use FUnIE-GAN for real-time image enhancement, while inspection teams might deploy ESRTGAN to analyze structural details. The API supports both batch processing for large datasets and real-time processing for live underwater video feeds.
Users can even compare multiple GAN models to find the best fit for their needs. For example, they can evaluate CycleGAN’s image quality (UIQM 3.91) relative to faster models. An "Auto Model" feature further simplifies this process by automatically selecting the most suitable GAN based on the image characteristics.
"It's absolutely brilliant - I share it with anyone who ever mentions Chat-GPT including when I did a panel for ARU on the AI revolution - the students were pretty excited at not paying a subscription!" - George Coxon
For underwater robotics applications that require edge deployment, NanoGPT supports lightweight models like FUnIE-GAN and SpiralGAN, enabling real-time processing on systems with limited resources. The platform streamlines model setup and optimization, letting engineers focus on integration rather than technical hurdles. This adaptability bridges the gap between precise lab results and practical field performance.
The interface is built with U.S.-based workflows in mind, using U.S. currency, MM/DD/YYYY date formats, and standard numeric formatting. By aligning high-performing GAN models with user-friendly deployment, NanoGPT delivers an effective solution for underwater restoration challenges.
Our analysis of processing speeds, image quality metrics, and performance in diverse underwater conditions highlights ESRTGAN as a strong contender for balancing real-time efficiency with top-notch image quality. This model shines in restoring colors and enhancing details, particularly in difficult environments like murky harbors or sediment-heavy waters. Its results are visually closer to real underwater scenes compared to traditional CNN-based methods.
That said, the right GAN model depends on your specific underwater application. For tasks like real-time robotics or SLAM, where speed is critical, UGAN stands out. Its processing speeds rival traditional fusion methods, making it a reliable choice for time-sensitive SLAM operations.
Meanwhile, FUnIE-GAN proves to be a valuable tool for underwater object detection. Its real-time enhancement capabilities significantly boost recognition accuracy, making it ideal for marine biologists identifying species or inspection teams detecting structural defects. However, its performance can vary depending on water conditions.
To address the trade-offs between speed and quality, compressed GAN models are emerging as a practical solution. These models achieve error rates as low as 1.2% - a marked improvement over CycleGAN's 11.5%. This makes them well-suited for underwater SLAM systems, enabling robust feature matching and real-time image processing, even in resource-constrained environments.
The computational demands of these models vary widely. While ESRTGAN offers exceptional visual results, it requires more processing power. On the other hand, compressed GANs strike a balance, offering solid performance for field deployments with limited computational resources.
Finally, platforms like NanoGPT simplify the integration of advanced GAN models into underwater imaging workflows. Whether you're processing large datasets in batch mode or working with live video feeds from underwater vehicles, NanoGPT provides flexible deployment options, meeting the diverse demands of underwater restoration tasks.
GAN models like ESRTGAN and UGAN have transformed underwater image restoration by tackling issues like color distortion, low contrast, and blurriness caused by the unique challenges of underwater environments. Unlike older techniques that depend on predefined filters or manual tweaks, these models leverage deep learning to create images that are both visually appealing and rich in detail.
Through training on extensive datasets, these GANs learn to reconstruct image features with precision, bringing back vibrant colors and sharp details. Their ability to process images in real time makes them a powerful tool for underwater exploration, marine research, and even underwater photography.
When it comes to running GAN models for real-time underwater applications, the hardware requirements can vary depending on the model's complexity and the speed you aim to achieve. At the core, you’ll need a high-performance GPU - something like an NVIDIA RTX series card - to manage the heavy computational tasks involved in real-time image processing. Pair this with at least 16 GB of RAM and a multi-core processor to keep things running smoothly.
If you're deploying this setup underwater, standard hardware won’t cut it. You’ll need ruggedized equipment designed to handle the challenges of such environments. This includes waterproofing and temperature-resistant features to ensure durability in harsh conditions. Ultimately, the exact hardware configuration will depend on the specific requirements and limitations of your project.
Currently, there isn't any detailed information about leveraging NanoGPT for testing or integrating GAN models specifically aimed at underwater image restoration. That said, NanoGPT provides access to a variety of AI models designed for text and image generation. Depending on your project's goals, these tools might be adaptable for such tasks. It's worth exploring NanoGPT's features further to see if they align with your needs.