Recreating Spectral Response from 6-Channel Color Sensor

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  • #1
AxisCat
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Hi All,

This is a project I started a couple of years ago then got stuck or bored and stopped working on it. I am thinking about picking back up where I left off. I am using a AMS AS7262 color sensor with the following overlapping channels: 450, 500, 550, 570, 600 and 650 nm, each with 40nm FWHM.

I used a Digikröm CM110 Monochromator and stepped through the spectrum in 1nm increments saving the output from the sensor to a file. My light source was a standard 100 watt halogen household bulb. This is what I measured:
chart.jpg

The continuous dark blue curve is from a photodiode I am trying to use as a reference. I understand this is really hard stuff to do with the limited equipment I have available. Is it even possible to recreate a fairly accurate spectral response using just these 6 discrete channels? The manufacturer provides some information that eludes to it being possible.

Anyone have any thoughts?

Thanks,
Axis
 
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  • #2
AxisCat said:
Hi All,

This is a project I started a couple of years ago then got stuck or bored and stopped working on it. I am thinking about picking back up where I left off. I am using a AMS AS7262 color sensor with the following overlapping channels: 450, 500, 550, 570, 600 and 650 nm, each with 40nm FWHM.

I used a Digikröm CM110 Monochromator and stepped through the spectrum in 1nm increments saving the output from the sensor to a file. My light source was a standard 100 watt halogen household bulb. This is what I measured:
View attachment 336147
The continuous dark blue curve is from a photodiode I am trying to use as a reference. I understand this is really hard stuff to do with the limited equipment I have available. Is it even possible to recreate a fairly accurate spectral response using just these 6 discrete channels? The manufacturer provides some information that eludes to it being possible.

Anyone have any thoughts?

Thanks,
Axis

Off the top of my head, I suggest that you first normalize each channel and then assign/compute wavelengths according to ratios of the different channels- that's generally how color vision works.
 
  • #3
I appreciate the reply. The "mapping function" is the part I am stuck on. Someone suggested Fourier transforms because the curves looked like filters and the math can be reversed. That looked really complicated so I haven't researched it any further. Another person's thought was using a matrix to calibrate. The input matrix would be 6x1 (sensor output x 6-channels), the correction matrix would be 6x300 (700nm - 400nm), and the output matrix would be a 1x300 representing the spectral response from 400-700nm. I really don't know which direction to take with this.
 

FAQ: Recreating Spectral Response from 6-Channel Color Sensor

What is a spectral response, and why is it important for a 6-channel color sensor?

A spectral response refers to the sensitivity of a sensor to different wavelengths of light. It is crucial for a 6-channel color sensor because it determines how accurately the sensor can capture and differentiate between various colors and intensities of light. This is important for applications requiring precise color measurement and reproduction, such as in imaging, photography, and quality control in manufacturing.

How does a 6-channel color sensor differ from traditional RGB sensors?

A traditional RGB sensor typically has three channels corresponding to red, green, and blue light. In contrast, a 6-channel color sensor has six channels, allowing it to capture a broader and more detailed spectrum of light. This additional data can improve color accuracy and enable more sophisticated color analysis and processing, making it suitable for more demanding applications.

What methods can be used to recreate the spectral response from a 6-channel color sensor?

Recreating the spectral response from a 6-channel color sensor often involves calibration and mathematical modeling. Common methods include using known reference materials with well-characterized spectral properties, applying machine learning algorithms, and employing interpolation techniques. These methods help in accurately mapping the sensor's raw data to a meaningful spectral response.

What are the challenges in recreating spectral response from a 6-channel color sensor?

Challenges include dealing with noise and inaccuracies in sensor readings, the complexity of the calibration process, and the need for precise reference data. Additionally, the mathematical models used to interpret the sensor data must be robust and able to handle variations in lighting conditions and material properties. Ensuring consistency and repeatability in measurements is also a significant challenge.

What applications benefit most from using a 6-channel color sensor with accurate spectral response recreation?

Applications that benefit the most include high-precision color matching in printing and textile industries, advanced imaging systems in medical diagnostics, environmental monitoring, and scientific research requiring detailed spectral analysis. Additionally, industries involved in quality control and material identification can greatly benefit from the enhanced accuracy and detail provided by a 6-channel color sensor.

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