A study was made at the Bhabha Atomic Research Center to measure the hearing levels of persons working in a noisy environment. Two different workplaces, central air-conditioning plant and glass flowing shops, where a number of persons were exposed to noise levels exceeding 85 dB(A) were chosen. The occupational exposure to noise was determined using a sound level meter, an octave band filter and a personal noise dose meter. The hearing levels of persons exposed to these high levels of noise and a control group not exposed to occupational noise were measured by means of a pure-tone audiometer in a specially-build booth. These persons, aged between 20 to 60 years, were divided into four age groups for the study. The low ambient noise levels in the booth were measured using correlation technique since such low signals cannot be detected by an ordinary sound level meter. The audiometric findings and the results of the noise level survey are discussed in this paper.
Ahgtraet. This paper describes a Z-80 microprocessor-based image analyzer developed for global parameter evaluation of images over a 256 × 256 pixel frame. It consists of a microscope, coa scanner, 6-bit video ADC, Z-80 computer and an image display monitor. Facilities are provided for feature erosion/dilation and halo correction. The paper also presents the details of another more powerful user microprogrammabie HPI000 minicomputer-based image analysis system under development. This system consists of an optical microscope/epidiascope coupled to a cbalnicon scanner. Here the 512 x 512 pixel image is acquired with 8-bit resolution. It provides for shading correction, auto-delineation, image processing and image analysis functions for evaluation of various basic and derived parameters. Both the systems are software intensive and are realised according to requirements of quantitative metallography. They can also be used for analysis of/mages obtained in the fields of biology, medicine, geological survey, photography and space.
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