Color sensors have become an integral part of many modern devices, enabling advanced color capture and detection capabilities. One such sensor is the Nix color sensor, developed by Nix Sensor Ltd. In this article, we’ll take a closer look at how the Nix color sensor works.
An Overview of the Nix Color Sensor
The Nix color sensor is a small, low-power spectral sensor that can detect and measure color from 350nm to 850nm wavelengths. This allows it to sense a wide gamut of colors across the visible light spectrum. The sensor was designed by Nix to enable mobile color capture and measurement in a variety of consumer applications.
At the heart of the Nix color sensor is a custom optical filter and specialized photodetector array. The filter enables the sensor to sample the color spectrum at very precise wavelengths. The photodetector array then converts these spectral samples into digital RGB color data. This proprietary approach is what sets Nix technology apart from traditional RGB sensors.
In addition to superior color fidelity, the Nix sensor is also highly configurable. Users can program the sensor’s sensitivity and output to match their specific application needs. This flexibility makes the sensor suitable for a wide range of uses.
Key Components and Operating Principles
The Nix color sensor consists of two core components:
- The optical filter array
- CMOS photodetector array
Let’s look at each of these in more detail:
Optical Filter Array
The optical filter array is composed of over 100 nano-scale Fabry-Pérot optical filters arranged in a mosaic layout. Each filter is designed to transmit light at specific wavelength ranges across the visible color spectrum. This allows the filter array to sample the color spectrum at 5nm increments.
The filter mosaic is produced using advanced MEMS (micro-electromechanical systems) processing techniques. Each filter is finely tuned by controlling the cavity spacing during manufacturing. This process enables a high level of precision and reproducibility.
CMOS Photodetector Array
Below the optical filter array is a complementary metal–oxide–semiconductor (CMOS) photodetector array. Each photodetector measures the light transmitted through the filter above it. The intensity of light measured at each wavelength is then converted into a digital signal.
The photodetector array is fabricated using standard commercial CMOS technology. This allows the integration of sensors and signal processing circuitry onto a single chip. The array typically consists of over 100 individual photodetectors matched to the filters above.
By combining the filter array with the underlying CMOS photodetectors, the Nix sensor can sample the visible color spectrum at nanometer resolution. This spectral sampling capability is the key to the sensor’s highly accurate color reproduction.
Operating Principle
Here is a simple overview of how the Nix color sensor operates:
- Light from the environment hits the optical filter array
- Each filter transmits a narrow band of wavelengths onto the photodetector below it
- The photodetectors measure the intensity of light at each transmitted wavelength
- The spectral intensity readings are converted into digital signals
- A color processing algorithm converts the spectral data into sRGB values
- The sRGB value represents the color measured by the sensor
By sampling many narrow wavelength bands across the color spectrum, the sensor can reconstruct the true color with a high degree of fidelity. This overcomes the limitations of traditional RGB sensors that rely on just three broad wavelength bands.
Key Performance Characteristics
Let’s look at some key characteristics that enable the excellent color performance of the Nix sensor:
High Color Accuracy
The Nix sensor achieves a high level of color accuracy due to its spectral sampling method. By measuring many discrete wavelengths, the sensor minimizes metameric effects. This allows it to distinguish subtle color differences that humans can perceive.
In independent testing, the Nix sensor achieves an average CIE Delta E color difference of less than 1. This means it can accurately match colors to within human perceptibility thresholds.
Wider Gamut Coverage
By sampling beyond the range of RGB sensors, the Nix can detect colors across a wider gamut. The Nix sensor can achieve over 110% sRGB gamut coverage and over 95% Adobe RGB coverage.
This allows the sensor to reproduce more vivid, saturated colors that lie outside the conventional sRGB color space.
Flexible Configuration
Users can program the Nix sensor’s sensitivity and output to suit different applications. For example, it can be configured for different light levels or to optimize color accuracy vs sensor sensitivity.
The sensor data output can also be configured as raw spectral data or processed into different color formats like sRGB, Adobe RGB etc.
Low Power Consumption
The CMOS photodetector array is fabricated using a 180nm process. This enables lower power consumption compared to older CMOS process nodes.
At full operation, the Nix sensor consumes less than 10mW of power. This allows integration into power-constrained mobile devices.
Applications
Thanks to its versatile capabilities, the Nix color sensor enables a variety of applications:
Mobile Photography
The sensor can be integrated into smartphone cameras to enhance color accuracy and gamut. This provides users with dSLR-like color quality from their mobile device.
Color Measurement Devices
Portable color measurement devices can be created using the Nix sensor, from colorimeters to spectrophotometers. This has applications in design, manufacturing, healthcare and more.
Smart Home Devices
IoT devices can use the Nix sensor to detect and analyze colors. This enables features like smart lighting, color matching, food quality monitoring, etc.
Industrial Automation
The sensor can enable robotics and other automation systems to accurately detect different colored objects for tasks like automated sorting.
Medical Devices
Medical diagnostic devices can use the Nix sensor for non-invasive skin measurements or analyzing bodily fluids.
Wearable devices can also leverage the sensor for skin composition analysis and health monitoring.
Advantages Over Traditional Color Sensing
Let’s summarize some of the key advantages the Nix sensor provides over traditional RGB color sensors:
| Nix Sensor | RGB Sensor |
|---|---|
| Captures full visible spectrum at high resolution | Samples only three broad wavelength bands |
| Minimizes metameric effects | Susceptible to metameric errors |
| Achieves excellent color accuracy (Delta E < 1) | Moderate color accuracy (Delta E ~3-5) |
| 110%+ sRGB gamut coverage | Up to 100% sRGB gamut |
| Flexible configuration options | Fixed configuration |
| Lower power consumption | Higher power needs |
By overcoming the limitations of RGB sensors, the Nix enables a new level of color fidelity and customization for various applications.
Conclusion
The Nix color sensor provides highly accurate, customizable color detection by utilizing spectral sampling. Key features like the nano-optical filter array, CMOS photodetector array and configurable outputs enable it to outperform traditional RGB color sensors.
With its balance of high performance and efficiency, the Nix sensor makes enhanced color capture possible in mobile, industrial, medical and IoT applications. As color technology continues to advance, sensors like Nix will open up new possibilities for how color is exploited across consumer and industry use-cases.
