Subpixel resolution with steerable filters

1994 ◽  
Author(s):  
James C. Brakefield
Keyword(s):  
Steerable Filters ◽  
Subpixel Resolution

Subpixel resolution in CdTe Timepix3 pixel detectors

2018 ◽  
Vol 25 (6) ◽  
pp. 1650-1657 ◽  
Author(s):  
Mohamad Khalil ◽  
Erik Schou Dreier ◽  
Jan Kehres ◽  
Jan Jakubek ◽  
Ulrik Lund Olsen
Keyword(s):  
Single Photon ◽  
Weighted Average ◽  
European Synchrotron Radiation Facility ◽  
Time Of Arrival ◽  
Pixel Detector ◽  
Step Size ◽  
X Ray ◽  
Pixel Detectors ◽  
Individual Photon ◽  
Subpixel Resolution

Timepix3 (256 × 256 pixels with a pitch of 55 µm) is a hybrid-pixel-detector readout chip that implements a data-driven architecture and is capable of simultaneous time-of-arrival (ToA) and energy (ToT: time-over-threshold) measurements. The ToA information allows the unambiguous identification of pixel clusters belonging to the same X-ray interaction, which allows for full one-by-one detection of photons. The weighted mean of the pixel clusters can be used to measure the subpixel position of an X-ray interaction. An experiment was performed at the European Synchrotron Radiation Facility in Grenoble, France, using a 5 µm × 5 µm pencil beam to scan a CdTe-ADVAPIX-Timepix3 pixel (55 µm × 55 µm) at 8 × 8 matrix positions with a step size of 5 µm. The head-on scan was carried out at four monochromatic energies: 24, 35, 70 and 120 keV. The subpixel position of every single photon in the beam was constructed using the weighted average of the charge spread of single interactions. Then the subpixel position of the total beam was found by calculating the mean position of all photons. This was carried out for all points in the 8 × 8 matrix of beam positions within a single pixel. The optimum conditions for the subpixel measurements are presented with regards to the cluster sizes and beam subpixel position, and the improvement of this technique is evaluated (using the charge sharing of each individual photon to achieve subpixel resolution) versus alternative techniques which compare the intensity ratio between pixels. The best result is achieved at 120 keV, where a beam step of 4.4 µm ± 0.86 µm was measured.

A Fast CMOS Optical Position Sensor With High Subpixel Resolution

2004 ◽  
Vol 53 (1) ◽  
pp. 116-123 ◽  
Author(s):  
N. Massari ◽  
L. Gonzo ◽  
M. Gottardi ◽  
A. Simoni
Keyword(s):  
Position Sensor ◽  
Optical Position ◽  
Subpixel Resolution

An Efficient Method for Tensor Voting Using Steerable Filters

2006 ◽  
pp. 228-240 ◽  
Author(s):  
Erik Franken ◽  
Markus van Almsick ◽  
Peter Rongen ◽  
Luc Florack ◽  
Bart ter Haar Romeny
Keyword(s):  
Efficient Method ◽  
Tensor Voting ◽  
Steerable Filters

Preattentive Colour Features by Steerable Filters

1995 ◽  
pp. 464-472 ◽  
Author(s):  
Udo Mahlmeister ◽  
Bertil Schmidt ◽  
Gerald Sommer
Keyword(s):  
Steerable Filters ◽  
Colour Features

Narrow directional steerable filters in motion estimation

2008 ◽  
Vol 110 (2) ◽  
pp. 192-211 ◽  
Author(s):  
Dimitrios S. Alexiadis ◽  
George D. Sergiadis
Keyword(s):  
Motion Estimation ◽  
Steerable Filters

Fibre Orientation Control Related to Papermaking

2006 ◽  
Author(s):  
A. Carlsson ◽  
F. Lundell ◽  
L. D. So¨derberg
Keyword(s):  
Shear Flow ◽  
Flow Field ◽  
Surface Structure ◽  
Fibre Orientation ◽  
Flow Direction ◽  
Glass Plate ◽  
Ccd Camera ◽  
Plate Surface ◽  
Steerable Filters ◽  
Fibre Suspension

The wall effect on the orientation of fibres suspended in a shear flow has been studied experimentally. A fibre suspension, driven by gravity down an inclined glass plate, constitutes the shear flow field. A CCD-camera was mounted underneath the flow in order to visualize the flow. The orientation of fibres in the plane perpendicular to the plate was determined, by using the concept of steerable filters. In a region close to the smooth plate surface the fibres oriented themselves perpendicular to the flow direction. This did not occur when the surface structure was modified with ridges.

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