Limits...
HyperCube: A Small Lensless Position Sensing Device for the Tracking of Flickering Infrared LEDs.

Raharijaona T, Mignon P, Juston R, Kerhuel L, Viollet S - Sensors (Basel) (2015)

Bottom Line: Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs) with an accuracy much greater than the one dictated by the pixel pitch.The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons.Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

View Article: PubMed Central - PubMed

Affiliation: Aix-Marseille Université, ISM UMR 7287, 13288, Marseille Cedex 09, France. thibaut.raharijaona@univ-amu.fr.

ABSTRACT
An innovative insect-based visual sensor is designed to perform active marker tracking. Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs) with an accuracy much greater than the one dictated by the pixel pitch. With a size of only 1 cm3 and a mass of only 0.33 g, the lensless sensor, called HyperCube, is dedicated to 3D motion tracking and fits perfectly with the drastic constraints imposed by micro-aerial vehicles. Only three photosensors are placed on each side of the cubic configuration of the sensing device, making this sensor very inexpensive and light. HyperCube provides the azimuth and elevation of infrared LEDs flickering at a high frequency (>1 kHz) with a precision of 0.5°. The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons. Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

No MeSH data available.


Related in: MedlinePlus

Sketch diagram of the HyperCube signal processing algorithm. (A) Top view: the sensor measures the azimuth φ. The left part shows the IR LED modulated at a frequency noted fi (1 kHz, 3.5 kHz or 11.5 kHz). In this view, HyperCube is composed of two photosensors Ph1 and Ph2 with their respective cosine-like angular sensitivities corresponding to Sides A and C of the sensor (see Figure 2A). An analog band-pass filter acts as a demodulator to extract the signal corresponding to the frequency fi of the IR LED, and an analog low-pass filter section with the cut-off frequency of 100 Hz reduces the high-frequency noise and prevents the subsequent analog-to-digital conversion from any aliasing effects. The digital processing consists of computing for each frequency fi the ratio of the relative difference to the sum between the two signals  to yield the HyperCube sensor output signal; (B) Side view: the same signal processing is applied on the signal provided by the photosensor Ph3 (Side B in Figure 2A) of HyperCube and a virtual photosensor, which is the sum of the photosensors Ph1 and Ph2.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4541889&req=5

f9-sensors-15-16484: Sketch diagram of the HyperCube signal processing algorithm. (A) Top view: the sensor measures the azimuth φ. The left part shows the IR LED modulated at a frequency noted fi (1 kHz, 3.5 kHz or 11.5 kHz). In this view, HyperCube is composed of two photosensors Ph1 and Ph2 with their respective cosine-like angular sensitivities corresponding to Sides A and C of the sensor (see Figure 2A). An analog band-pass filter acts as a demodulator to extract the signal corresponding to the frequency fi of the IR LED, and an analog low-pass filter section with the cut-off frequency of 100 Hz reduces the high-frequency noise and prevents the subsequent analog-to-digital conversion from any aliasing effects. The digital processing consists of computing for each frequency fi the ratio of the relative difference to the sum between the two signals to yield the HyperCube sensor output signal; (B) Side view: the same signal processing is applied on the signal provided by the photosensor Ph3 (Side B in Figure 2A) of HyperCube and a virtual photosensor, which is the sum of the photosensors Ph1 and Ph2.

Mentions: A Gaussian-like directivity function mimics the Gaussian angular sensitivity function of flies' photoreceptors [18,19]. The Gaussian-like angular sensitivity of each photosensor can be defined by the angle of acceptance, denoted Δρ. The angle Δρ is defined as the full width at half maximum, as depicted later in Figure 9. The Gaussian-like angular sensitivity of a photosensor is given by:(1)σ(θ)=2πln(2)πΔρe−4ln(2)(θ2Δρ2)where θ is the angle between the photosensor's optical axis and that of a point light source. We also introduce the cosine-like angular sensitivity function σ, such that:(2)σ(θ)={cos(θ)if/θ/≤π20else


HyperCube: A Small Lensless Position Sensing Device for the Tracking of Flickering Infrared LEDs.

Raharijaona T, Mignon P, Juston R, Kerhuel L, Viollet S - Sensors (Basel) (2015)

Sketch diagram of the HyperCube signal processing algorithm. (A) Top view: the sensor measures the azimuth φ. The left part shows the IR LED modulated at a frequency noted fi (1 kHz, 3.5 kHz or 11.5 kHz). In this view, HyperCube is composed of two photosensors Ph1 and Ph2 with their respective cosine-like angular sensitivities corresponding to Sides A and C of the sensor (see Figure 2A). An analog band-pass filter acts as a demodulator to extract the signal corresponding to the frequency fi of the IR LED, and an analog low-pass filter section with the cut-off frequency of 100 Hz reduces the high-frequency noise and prevents the subsequent analog-to-digital conversion from any aliasing effects. The digital processing consists of computing for each frequency fi the ratio of the relative difference to the sum between the two signals  to yield the HyperCube sensor output signal; (B) Side view: the same signal processing is applied on the signal provided by the photosensor Ph3 (Side B in Figure 2A) of HyperCube and a virtual photosensor, which is the sum of the photosensors Ph1 and Ph2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4541889&req=5

f9-sensors-15-16484: Sketch diagram of the HyperCube signal processing algorithm. (A) Top view: the sensor measures the azimuth φ. The left part shows the IR LED modulated at a frequency noted fi (1 kHz, 3.5 kHz or 11.5 kHz). In this view, HyperCube is composed of two photosensors Ph1 and Ph2 with their respective cosine-like angular sensitivities corresponding to Sides A and C of the sensor (see Figure 2A). An analog band-pass filter acts as a demodulator to extract the signal corresponding to the frequency fi of the IR LED, and an analog low-pass filter section with the cut-off frequency of 100 Hz reduces the high-frequency noise and prevents the subsequent analog-to-digital conversion from any aliasing effects. The digital processing consists of computing for each frequency fi the ratio of the relative difference to the sum between the two signals to yield the HyperCube sensor output signal; (B) Side view: the same signal processing is applied on the signal provided by the photosensor Ph3 (Side B in Figure 2A) of HyperCube and a virtual photosensor, which is the sum of the photosensors Ph1 and Ph2.
Mentions: A Gaussian-like directivity function mimics the Gaussian angular sensitivity function of flies' photoreceptors [18,19]. The Gaussian-like angular sensitivity of each photosensor can be defined by the angle of acceptance, denoted Δρ. The angle Δρ is defined as the full width at half maximum, as depicted later in Figure 9. The Gaussian-like angular sensitivity of a photosensor is given by:(1)σ(θ)=2πln(2)πΔρe−4ln(2)(θ2Δρ2)where θ is the angle between the photosensor's optical axis and that of a point light source. We also introduce the cosine-like angular sensitivity function σ, such that:(2)σ(θ)={cos(θ)if/θ/≤π20else

Bottom Line: Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs) with an accuracy much greater than the one dictated by the pixel pitch.The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons.Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

View Article: PubMed Central - PubMed

Affiliation: Aix-Marseille Université, ISM UMR 7287, 13288, Marseille Cedex 09, France. thibaut.raharijaona@univ-amu.fr.

ABSTRACT
An innovative insect-based visual sensor is designed to perform active marker tracking. Without any optics and a field-of-view of about 60°, a novel miniature visual sensor is able to locate flickering markers (LEDs) with an accuracy much greater than the one dictated by the pixel pitch. With a size of only 1 cm3 and a mass of only 0.33 g, the lensless sensor, called HyperCube, is dedicated to 3D motion tracking and fits perfectly with the drastic constraints imposed by micro-aerial vehicles. Only three photosensors are placed on each side of the cubic configuration of the sensing device, making this sensor very inexpensive and light. HyperCube provides the azimuth and elevation of infrared LEDs flickering at a high frequency (>1 kHz) with a precision of 0.5°. The minimalistic design in terms of small size, low mass and low power consumption of this visual sensor makes it suitable for many applications in the field of the cooperative flight of unmanned aerial vehicles and, more generally, robotic applications requiring active beacons. Experimental results show that HyperCube provides useful angular measurements that can be used to estimate the relative position between the sensor and the flickering infrared markers.

No MeSH data available.


Related in: MedlinePlus