Abstract

An optoelectronic in-line imaging system for particle sizing is described. The images are scanned by two CCD cameras viewing the same object field that is illuminated with two pulses. One of the cameras is double exposed and the other is activated only during the second pulse. Two successive analogical subtractions between the video output signals gives the sign of the transverse velocity vector. Out-of-focus images are deconvolved with the assumption of a Gaussian point-spread function (PSF) whose spatial parameter σ increases with the defocusing distance z. In the case of low particle density, an algorithm based on the exploitation of the power spectral density is used to estimate the particle diameter. This method can be applied to the case of fast-moving particles (e.g., υ < 500 m/s). The accuracy of the size measurement is better than 10% in the diameter range 20–160 μm. The main result is that this accuracy is obtained with an amount of defocusing in the range [−2, 2] mm. Thus, the depth of field is significantly extended in comparison with a conventional microscopic imaging system.

© 1996 Optical Society of America

Full Article  |  PDF Article

References

You do not have subscription access to this journal. Citation lists with outbound citation links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Cited By

You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Figures (9)

You do not have subscription access to this journal. Figure files are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Equations (15)

You do not have subscription access to this journal. Equations are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription

Metrics

You do not have subscription access to this journal. Article level metrics are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.

Contact your librarian or system administrator
or
Login to access OSA Member Subscription