Warner Lambert Technologies, Inc.

Cambridge Instrument Company, Inc.

John K Michalik

A circuit and method for converting signals from a photoelectric image sensor into digital signals containing information as to a characteristic of the sensor signals. The photoelectric image sensor provides output pulses having characteristic determined by the manner in which light is incident thereon and this, in turn, is determined by a light influencing medium in an optical path between a light source and the image sensor. In particular, the peak amplitude of each signal from the sensor is determined and then converted into a digital signal containing information as to the peak amplitude. This is accomplished by detecting the rise of each sensor signal to a peak amplitude and then holding a signal level corresponding to the peak level of the sensor signal as the sensor signal falls in amplitude for a time at least equal to the time for acquiring or converting into the digital signal. In particular, there is provided a peak detector circuit operatively connected to the photoelectric image sensor for detecting the peak amplitudes of signals obtained from the sensor and an analog to digital converter connected to the peak detector circuit for providing digital signals containing information as to peak amplitudes of the sensor signals. The peak detector circuit comprises a portion responsive to the rise of each sensor signal to a peak amplitude and a portion for holding a signal level corresponding to the peak level of each sensor signal as the sensor signal falls in amplitude for a time at least equal to the acquisition time or conversion time of the analog-to-digital converter.

Signal processing for optical image sensor

An automatic refractometer comprising a photosensitive device having a relatively narrow dynamic range in the form of a linear scanned array including a plurality of photoelectric elements each providing an output pulse during a scan and the amplitude of each pulse being determined by the amount of illumination of the corresponding element by incident light, an optical system for directing light onto the array in a manner such that the particular photoelectric elements of the array which are illuminated by the light are determined by the index of refraction of a light transmitting substance placed in operative association with the optical system, a circuit for converting signals from the array into digital signals containing information as to the amplitudes of the signals from the array, a digital processing circuit for storing respective signals from reference and sample substances placed in operative association with the optical system and for computing the index of refraction of the sample substance by means of a comparison of the stored reference and sample information, and apparatus for providing a read out of the computed result. The digital processing circuit also calculates the percent solids in the sample substance, and the circuit also includes a plurality of channels for containing information to provide different interpretation of the index of refraction computed thereby. The circuit for converting array signals into digital signals comprises a peak detector circuit for detecting peak amplitudes of signals obtained from scanning the array and an analog-to-digital converter for providing digital signals containing information as to peak amplitudes of the array signals. There is also provided arrangements for measuring the temperatures of the sample substance and comparing to a reference for applying a temperature correction to the computed index of refraction, monitoring and regulating the temperature of the component of the optical system to which the sample substance is exposed, and monitoring and regulating the intensity of light incident on the array.

Automatic refractometer

A current to frequency converter comprising a current source, for example a photocell, a voltage to frequency converter, an integrator in the feedback loop of the converter, the current source being connected to the summing junction of the converter and integrator such that the frequency of output pulses from the converter is directly proportional to the magnitude of current injected from the converter to the summing junction, and a controlled circuit for attenuating the current injected from the converter to the summing junction to increase the frequency of output pulses. The controlled attenuating circuit includes a transistor switching arrangement for introducing increased resistance in the path for current injected from the converter to the summing junction in response to the presence of a control signal.

Current to frequency converter switched to increased frequency when

An exposure and camera control system comprising a keyboard for providing input information relating to film parameters and camera type, a light to frequency converter for providing signals having a frequency proportional to the intensity of light to be used in exposing the film, and a control operatively connected to the information providing keyboard and to the light to frequency converter for determining the film exposure time and for providing signals for controlling film exposure to light and signals for controlling film transport when the exposure is complete. The control includes a microprocessor, programmable memory, and input/output interface components. A display operatively connected to the control provides visual display of information inputs to the control and of calculated quantitites such as exposure time. A printer operatively connected to the control provides a hard copy record of the displayed information. A light detector operatively connected to the control includes a mirror normally positioned in the optical path for directing light to the light to frequency converter which mirror is moved out of the optical path before an exposure is made. Sensors in the camera being controlled provide signals to the control indicative of film travel and presence of a new film roll in the camera. The exposure and camera control has advantageous use with a microscope in apparatus for making photomicrographs.

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Sloan, NY, United States of America

John K Michalik