Abstract: In an image composer includes a storage for storing a first and a second image, a region classifier compares the first image with the second image to extract as a non-common sub-region a partial region of one of the two images that does not have a similar pixel property to that of the other image. An image composing unit superimposes the extracted non-common sub-region of one of the images onto the other image to produce a resultant composite image.

Abstract: An image interpretation apparatus including a registration section, an image search section, and an image interpretation section is provided. The registration section registers an object image in an object database. The image search section searches a type, an attribute, and an arrangement, or a combination of the object images included in an input image. The image interpretation section interprets semantics of the input image based on the arrangement, the combination, or the like. Due to this configuration, plural pieces of semantics can be given to a single image, and a complex subsequent-stage process can be performed according to an image interpretation result.

Abstract: Disclosed herein is an optical modulator including an optical waveguide structure for converting an input beam into first and second output beams, an electrode for applying an electric field to the optical waveguide structure, so as to switch between a first mode where the input beam is converted into the first output beam and a second mode where the input beam is converted into the second output beam, first and second photodetectors for detecting the powers of the first and second output beams, respectively, and a bias circuit for applying a bias to the electrode so that the ratio in output level between the first and second photodetectors becomes constant. With this configuration, an operation point can be stabilized without the need for superimposition of a low-frequency signal, thereby suppressing intersymbol interference.

Abstract: An optical wavelength stabilizing system including a laser diode for emitting signal light, a Peltier element for controlling a temperature of the laser diode, and a drive circuit for driving the Peltier element. The signal light is branched into two components by an optical coupler. In an optical path of one of the two components obtained by the optical coupler, there is inserted an optical filter having a portion whose transmittance continuously changes according to wavelength. The signal light component passed through the portion of the optical filter is detected by a photodetector. An output current from the photodetector is converted into a voltage, which is then input into a comparator. The comparator compares the voltage output from the photodetector and a reference voltage to input a voltage difference therebetween into the drive circuit.

Abstract: The control circuit for supplying a driving current to a laser diode makes it possible to keep the laser driving current variable in a wide range.

Abstract: The optical amplifier includes a doped fiber doped with a rare earth element, a pumping light source, means for introducing signal light and pumping light into the doped fiber, detection means for detecting whether or not amplified signal light is included in light outputted from the doped fiber, and means for decreasing the intensity of the pumping light when it is detected that amplified signal light is not included. It can be possible to eliminate an influence of an optical surge arising from a characteristic of the doped fiber.

Abstract: A slice amplifier using field effect transistors (FET's) is provided which is suitable for achieving a correct discrimination of logics "0" and "1" of an input signal (S.sub.in) at very high speed by reshaping the input signal (S.sub.in) into rectangular shaped pulses (S.sub.out). The top and bottom of each pulse are determined to predetermined constant levels by using a first FET (T.sub.1) and a second FET (T.sub.2) with the aid of a first monitor and control unit (41) and second monitor and control unit (42). The first and second monitor and control units (41, 42) monitor the drain voltages of the first and second FET's (T.sub.1, T.sub.2) and control the gate-source voltages thereof, respectively, so as to realize the predetermined constant levels.

Abstract: A semiconductor laser driving device using FET's as a positive element in a bias current supply circuit and a pulse current supply circuit, and having compensating circuits for compensating differences in the characteristics of the FET's and a laser diode used in the driving device. Also a pulse amplifier suitable for use as the pulse current supply circuit in the semiconductor driving device, which circuit cuts off a pulse top side portion and a pulse base side portion of an input pulse with respect to a mesial point of the input pulse to obtain an output pulse having a desired pulse amplitude in response to a control signal, without varying a pulse width.

Abstract: A semiconductor laser driving device using FET's as a positive element in a bias current supply circuit and a pulse current supply circuit, and having compensating circuits for compensating differences in the characteristics of the FET's and a laser diode used in the driving device. Also a pulse amplifier suitable for use as the pulse current supply circuit in the semiconductor driving device, which circuit cuts off a pulse top side portion and a pulse base side portion of an input pulse with respect to a mesial point of the input pulse to obtain an output pulse having a desired pulse amplitude in response to a control signal, without varying a pulse width.