Figure 1.
The webcam image sensor (Live! Cam Sync, Creative Labs) is located so that it is accessible to both fluid samples and specimens on microscope slides mounted under a coverslip.
The sensor exposed after removal of optics (A). The webcam after exposure of the sensor and protecting the surrounding with polyacrylamide resin (B) and after attaching a screw-cap (with an opening cut out for the sensor) of a 10 ml plastic centrifuge tube to form a sedimentation chamber (C).
Figure 2.
On-chip image of calibration slide 1951 USAF resolution test chart (A), which shows resolution of 45,3 line pairs (group 5, element 4) was obtained using the lookup table (http://en.wikipedia.org/wiki/1951_USAF_resolution_test_chart).
The length of element 1 in group 4 is 0. 15625 mm. The line width resolved is about 12 µm. (http://www.efg2.com/Lab/ImageProcessing/TestTargets/#Microcopy). On-chip image of calibration beads 50 to 350 µm in diameter (B). Still image obtained by pipetting urine sediment containing schistosome eggs from a patient with urinary schistosomiasis on top of an exposed, lensless webcam image sensor (C) and image used in training set to generate algorithm for computer vision (D). Green circles surround structures identified as “eggs”, red circles “not eggs” and yellow “uncertain/questionable”.
Figure 3.
Green circles mark the positions of manually labeled eggs, the light blue ones mark positions of parasites detected by computer vision.
Figure 4.
Image processing algorithm developed for the identification of Schistosoma haematobium eggs in urine sediment based on image capture on-chip using simple webcam.
Green circle marks an egg candidate; a light blue circle marks a doubtful egg candidate. Sequential stages of image processing and analysis yielded an algorithm capable of identifying eggs in the on-chip images.
Figure 5.
On-chip contact images of helminth eggs and larvae in stool samples.
(A) Individual Schistosoma mansoni eggs in stool sample from experimentally infected mouse from on-chip image obtained with the exposed sensor of sensor of a mobile phone (Sony-Ericsson C905). Note that the lateral spine can be seen in some eggs. In (B) S. mansoni eggs are seen in an ordinary microscope using 20×objective (Leica DMRB with AxioCam digital camera). Trichuris trichiura eggs are seen in images obtained on-chip (C) and under conventional microscope (D) microscope using 10×objective. On-chip images were obtained with S. mansoni. Strongyloides larvae (E) by on-chip imaging using a webcam sensor (Live! Cam Sync, Creative Labs).
Figure 6.
Schistosoma haematobium egg and calibration beads seen in on-chip image obtained with a mobile phone camera (Nokia E71) (A) compared to a similar area seen in a conventional light microscope using 10×objective (B).
Note effect of absent optics in on-chip imaging; accentuated dark margins of both the egg and marker beads in on-chip image as compared to image obtained with microscope. Beads are 50 to 350 µm in diameter. Bars are 10×100 pixels.