Liquid level detection in receptacles using a plenoptic camera to measure the surface topography of the liquid

Abstract

An apparatus for measuring a volume of liquid includes a support for receiving an at least partially transparent receptacle having at least one cavity for holding a liquid; a plenoptic camera facing the support; a pattern provided so as to be viewable through the receptacle by the plenoptic camera; and a control unit communicating with at least the camera and adapted to carry out the steps of: making at least one plenoptic image of the surface of the liquid by the plenoptic camera, determining a surface topography of the liquid on the basis of the at least one image, the surface topography of the liquid being measured at least partially based on distortion of the pattern, and calculating the volume of liquid based on the measured surface topography and at least one known dimension and/or position of at least part of the cavity.

1 . An apparatus for measuring a volume of liquid provided in at least one receptacle, said apparatus comprising:
 a support for receiving an at least partially transparent receptacle having at least one cavity for holding a liquid;   a plenoptic camera facing said support;   a pattern provided so as to be viewable through said at least partially transparent receptacle by said plenoptic camera; and   a control unit communicating with at least said camera and adapted to carry out the steps of:
 making at least one plenoptic image of the surface of the liquid by use of the plenoptic camera, 
 determining a surface topography of said liquid on the basis of said at least one image, the surface topography of the liquid being measured at least partially based on distortion of said pattern, and 
 calculating the volume of liquid based on the measured surface topography and at least one known dimension and/or position of at least part of said cavity. 
   
     
     
         2 . The apparatus according to  claim 1 , wherein said plenoptic camera is mounted on a scanning stage movable perpendicular to the optical axis of said plenoptic camera. 
     
     
         3 . The apparatus according to  claim 1 , wherein said pattern comprises least one of: a grid pattern, a random noise pattern, a raster pattern, a checkerboard pattern or any combination thereof. 
     
     
         4 . The apparatus according to  claim 1 , further comprising at least one illumination device. 
     
     
         5 . The apparatus according to  claim 4 , wherein said illumination device is adapted to produce a structured light pattern. 
     
     
         6 . The apparatus according to  claim 5 , wherein said pattern comprises at least one of: a grid pattern, a random noise pattern, a raster pattern, a checkerboard pattern or any combination thereof. 
     
     
         7 . The apparatus according to  claim 1 , further comprising a vibrator arranged to vibrate the surface of said liquid. 
     
     
         8 . The apparatus according to  claim 7 , wherein said vibrator is integrated into said support. 
     
     
         9 . The apparatus according to  claim 7 , wherein said vibrator is arranged to produce ultrasonic vibrations. 
     
     
         10 . The apparatus according to  claim 8 , wherein said vibrator is arranged to produce ultrasonic vibrations. 
     
     
         11 . A non-transitory computer readable medium having stored thereon a computer program product directly loadable into an internal memory of a digital computer, said digital computer program product comprising software code portions for causing an apparatus for measuring a volume of liquid provided in at least one receptacle, said apparatus comprising:
 a support for receiving an at least partially transparent receptacle having at least one cavity for holding a liquid;   a plenoptic camera facing said support;   a pattern provided so as to be viewable through said receptacle by said plenoptic camera; and   a control unit communicating with at least said camera,   wherein the software code portions, when run on the digital computer acting as said control unit, causing the apparatus to carry out the steps of:
 making at least one plenoptic image of the surface of the liquid by use of the plenoptic camera, 
 determining a surface topography of said liquid on the basis of said at least one image, the surface topography of the liquid being measured at least partially based on distortion of said pattern, and 
 calculating the volume of liquid based on the measured surface topography and at least one known dimension and/or position of at least part of said cavity.