Thermal sensor resolution. Truth!
Watch this video and you will be better informed than many self procalimed thermal experts. Paul Alisauskas, FYRLYT's lead thermal designer, offers a key insight that clears up common confusion about thermal sensor resolution. His expertise highlights a critical point: Thermal sensor size DOES NOT dictate thermal sensor resolution.
Understanding this is crucial because people easily misunderstand what's truly important in thermal imaging. This knowledge can actually save you thousands of dollars by helping you avoid overpaying for unnecessary features based on size misconceptions. FYRLYT wants to give you the real facts, based on science, so you can check for yourself and make smart choices for your specific needs.
FYRLYT Thermal Products. Remote mounted camera | Monocular | Riflescope | Avionics
Investing in thermal imaging equipment is a big decision and it is important to understand the strengths and limitations with the technology regardless of brand or price. It is very easy to over invest or worse be confused as to why it does not live up to your expectations especially in certain weather conditions.
Ask the FYRLYT design team your thermal questions
If this is your first purchase we encourage you to call us or message for a no obligation call back. We will listen to your requirements, answer questions and provide valuable advice few others can or are willing to provide. This is especially the case with remote mounting a thermal monocular on a vehicle roof with or without a spotlight. FYRLYT pioneered the specific integration of a thermal camera and spotlight by designing and building its own system, the FTV 640 right here in Australia.
Why the FTO 640-50 thermal rifle scope?
What do you need to spend to get a thermal riflescope that delivers real world performance in the field? Currently you have a wide choice of different brands offering a range of configurations that typically include several sensor sizes. Generally price increases with the size of the sensor as does its potential to deliver a more detailed image at greater distances. Prices in Australia range from $3000 to nearly $20000.
FYRLYT had a simple objective. Bring to market the best value Euro 640x512 12um sensor rifle scope without compromising any performance or features. Package this in a conventional 3 turret, 30mm tube design, familiar size and profile. For the working professional, the FTO 640-50 is a must see consideration. This thermal rifle scope was exhaustively tested and evolved by our team right here in Australia. We invite you to ask direct questions to decide whether the FTO 640-50 is the right fit for your thermal needs and expectations. If we believe another product would be more suitable we will say so with no reservation.
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FYRFLY - Aviation thermal camera
Building on the resounding success of FYRLYT's FTV 640 thermal remote mounted vehicle system, and spurred by the Australian aviation community's call for innovation, we set our sights skyward. PROJECT FYRFLY is poised to revolutionise aerial operations with an affordable, seamlessly integrated thermal camera system for avionic visual displays. Empower pilots with real-time thermal imagery, enhancing situational awareness and safety in challenging conditions. Its compact, lightweight design ensures effortless installation and operation across a range of aircraft and helicopters, making advanced thermal imaging accessible to all. PROJECT FYRFLY - where innovation takes flight. MORE INFO
THERMAL FAQS - (Frequently updated)
Welcome to FYRLYT Thermal Products FAQ! We understand that the world of thermal technology can be complex, filled with new terminology and promises of a super technology. Unfortunately, this has led to overzealous marketing practices, especially in the premium segment, where claims may not always align with real-world performance. Our goal is to cut through the hype and provide you with clear, factual information to help you make informed decisions.
This technology is transformative, but don't rely solely on influencer or reseller advice. Before investing in 1024 and 1280 sensors, take the time to learn the fundamentals to potentially save yourself thousands of dollars. They do have their applications but they are not for everybody and often not delivering what you may have been led to believe.
Contact the FYRLYT design team directly for expert, no-obligation guidance.
Best scope for you?
Investing in a quality thermal scope means you are faced with products ranging from approx $3000 to $20000. If you listen to the hype and some influencers you'd be forgiven for thinking that unless you choose 1024x768 or 1280x1024 specification you are missing out and not getting best performance. Our advice? Ensure you understand the truth about resolution and detection distances. It’s crucial to consider your typical use. As resources like the FYRLYT PPD video emphasise, understanding PPD and FOV is key. If you usually operate at higher magnifications – like 5x optical or more and you don’t need an exceptionally wide close-range view, then investing heavily in a 640, 1024, or 1280 sensor provides no advantage. A lower pixel count, would be a more cost-effective option and will perform the same if the pixel spacing and lens size are the identical. Consider this. For many people a scope such as the FYRLYT FTO 384-50 12um provides them the same detection ranges and capabilities of scopes like 640 and 1024 costing twice the amount or more. When you are at your familiar optical 5X magnification or above you are seeing the same fov and resolution if the lens and pixel spacing is the same. If you have any questions ask our design team direct with no obligation.
Optical v digital magnification
Conventional rifle scopes use optical magnification. They work by bending visible light through a series of lenses to physically enlarge the image of the target as you see it. This is an analogue zoom process, where moving lens elements within the scope provides true optical magnification, increasing the apparent size of objects in your field of view. You are literally seeing a larger optical representation of the scene. Thermal Scope Magnification: Base vs. Digital Zoom Thermal rifle scopes function differently. They don't magnify visible light; instead, they display a digital image representing heat energy. A thermal scope's base magnification is set by its sensor characteristics (size and pixel pitch) and the lens focal length. This base level defines the initial field of view and the angular resolution (PPD). Zooming in a thermal scope is typically digital zoom. This process crops and digitally enlarges the already processed thermal image. Unlike optical zoom, digital zoom in thermal scopes doesn't add more detail; it simply digitally enlarges the image.
Pixels per degree. Truth.
PPD, or Pixels Per Degree, represents the real angular resolution of a thermal sensor. It tells you how many pixels are packed into each degree of the sensor's Field of View (FOV). Think of it as the pixel density in your vision. Q: Why is PPD important? PPD is crucial because it directly dictates the level of detail a thermal sensor can resolve at a given distance. Higher PPD means finer detail, better object recognition, and increased detection range for small objects. Q: What's the PPD formula? PPD = (Sensor Size in Pixels - either horizontal or vertical) / (Field of View in Degrees - corresponding.) Q: What factors effect PPD? Pixel spacing on the thermal sensor and the lens focal length.
All about mK
Q: What does 'mK' NETD mean for thermal sensor sensitivity? 'mK' (milliKelvin) is the unit for Noise Equivalent Temperature Difference (NETD), a key measure of thermal sensor sensitivity. Lower mK values indicate higher sensitivity, meaning the sensor can detect smaller temperature variations and produce a higher contrast image. Q: Why should very low mK claims for uncooled sensors be viewed cautiously? Uncooled sensors, operating at ambient temperatures, inherently generate more thermal noise than cooled sensors. Achieving extremely low mK values (e.g., below 25mK) with uncooled technology presents significant engineering challenges. Claims of exceptionally low mK for uncooled sensors may be achieved through non-representative testing conditions (e.g., very slow frame rates, fast lenses) or heavy software processing, not truly reflecting raw sensor sensitivity.
Detection distance
While the Johnson Criteria is a historically important benchmark in thermal imaging, FYRLYT recommends Pixels Per Degree (PPD) verification for its clarity. The Johnson Criteria's flexibility can be misleadingly used in marketing by emphasising pixel counts. PPD offers a more direct and less ambiguous measure of performance. However, understanding the Johnson Criteria remains valuable for grasping fundamental thermal sensor principles. This "minimum resolvable temperature difference" is represented as ΔTmin. Here, Δ (Delta) signifies "change in" or "difference in" – specifically, temperature. Essentially, the Johnson Criteria means a sensor needs to see a sufficient Delta Temperature (ΔT) between an object and its background to detect or recognize it thermally. This temperature difference must overcome system noise, measured by Noise Equivalent Temperature Difference (NETD). Sensor spatial resolution, which defines the detail it can capture, is also critical. Industry standards, like SPIE Field Guides on Infrared Systems Engineering (SPIE Field Guides), emphasize these criteria for robust signal fidelity. The Johnson Criteria often uses a standard human figure (approximately 1.8m x 0.5m) as a reference object for analysis. The criteria then define the number of pixels required across the critical dimension of this object on the sensor image for different levels of task performance. These are generally accepted guidelines: (Please note the variances re the first paragraph) Detection (Presence): Roughly 2-3 pixels across the critical dimension. At this level, you can discern that something is there, but not its specific nature. Recognition (Classification): Around 6-8 pixels across the critical dimension. You can classify the object type (e.g., "vehicle", "person"), but lack finer detail. Identification (Specific Type): Approximately 12-15 pixels across the critical dimension. You can identify the specific object (e.g., "tank", "man with a rifle").
Pixels. Understanding microns.
Pixel pitch defines the distance between the center of one pixel and the center of its neighboring pixel on a thermal sensor array. Imagine pixels laid out in a grid; pixel pitch is the size of one unit of this grid, measured from the center of one pixel to the center of the next. It's typically measured in micrometers (µm), which are incredibly small units of length (millionths of a meter). Think of it like the spacing between individual LEDs in a screen, measured from the center of one LED to the next. This definition applies equally to both cooled and uncooled thermal sensors. The pixel pitch is a fundamental specification for all thermal sensors, regardless of whether they are cooled or uncooled. It is typically found in the sensor's datasheet or technical specifications provided by the manufacturer. Why is pixel pitch such an important specification for thermal sensors? Pixel pitch significantly impacts several key aspects of thermal sensor performance and characteristics, regardless of whether the sensor is cooled or uncooled: Sensor Physical Size: For a sensor with a specific pixel resolution (e.g., 640x512), a smaller pixel pitch leads to a physically smaller sensor. Conversely, a larger pixel pitch results in a larger sensor with less pixels per degree for a comparative lens. This is consistent for both cooled and uncooled designs.
FOV. Field of view.
The manufacturer should list the FOV in any specifications data. If not or you wish to clarify yourself the following allows you to calculate it. So, what is the field of view (FOV)? Imagine your thermal camera is like looking through a window. The FOV is just how wide and tall that window is – how much you can see! Why is FOV important? A wide window lets you see a big area (good for scanning). A narrow window zooms you in to see details far away. What controls how wide or narrow your window is? Two main things: Sensor Size (like window size): Think of the sensor inside your camera as the "window" that captures the heat picture. Bigger Sensor = Wider Window = Wider FOV. You see more of the scene. Sensor size is determined by its pixel dimensions AND the pixel pitch (size of each tiny pixel). Lens Focal Length (like how far you are from the window): Focal length is a number that comes with your lens, usually in millimeters (mm) too. Don't necessarily confuse this with lens diameter (the size of the glass!). Shorter Focal Length = Closer to Window = Wider FOV. You see more of the garden outside the window. Longer Focal Length = Further from Window = Narrower FOV. You're zoomed in, seeing just the rose bush.
Two sensor types
Uncooled thermal sensors detect infrared radiation through changes in sensor material properties. This technology yields cost-effective and compact sensors requiring minimal maintenance. Their practicality makes them well-suited for the vast majority of commercial thermal imaging applications, where affordability and ease of use are paramount. Any thermal camera or scope within the civilian consumer market regardless of brand or cost will utilise an uncooled sensor. Cooled sensors employ cryogenic cooling to significantly reduce thermal noise, enabling them to achieve superior sensitivity and detect extremely subtle temperature differences. However, this cooling mechanism adds substantial size and complexity. Cooled sensors are also considerably more expensive to manufacture, purchase, and maintain, often requiring specialized return-to-manufacturer servicing at extremely high cost. As a result, cooled sensors are predominantly used in specialised, high-performance applications, and are not typically found in mainstream thermal imaging products due to their cost, size, and demanding maintenance requirements.