Abstract: An object of the invention is to provide an image sensing apparatus capable of sensing an image in consideration of the influence of inserting/removing an optical filter, an image sensing method, a recording medium, and a program. To achieve this object, a brightness value calculation unit calculates the first brightness value representing the brightness of part or all of an object which is imaged on a CCD image sensing element. A brightness value correction unit calculates the second brightness value by correcting the first brightness value calculated by the brightness value calculation unit on the basis of the light reduction amount generated by inserting an ND filter. A system controller controls an optical system and signal processing in a DSP circuit by using the second brightness value calculated by the brightness value correction unit.

Abstract: A dc level control method for holding a dc level of a clamp portion in an electric signal to be a prescribed value is disclosed, wherein the method comprises the steps of: comparing a dc level of a sampling interval in said electric signal with a predetermined reference value to obtain a difference between said dc level and said reference value using an A/D converting section for dc level comparison which has a lower bit resolution than an A/D converting section for digital signal processing of said electric signal; and feeding back a clamp signal to said electric signal so that said obtained difference between said dc level and said reference value substantially becomes zero. This method is suitable for applying to a signal processing system for a solid state imaging apparatus.

Abstract: Methods and apparatus for image acquisition utilize a charge coupled device having a photosensitive region that responds to an applied transfer signal by transferring charge accumulated on the collection sites to the corresponding readout sites. The non-photosensitive region responds to a read signal, applied independently of the transfer signal, by outputting (e.g., to the host camera or image acquisition system) charges on the readout sites. The methods and apparatus take advantage of the inherent storage capability of the non-photosensitive sites by using them to hold image information pending application of the readout signal, thereby, conserving host resources.

Abstract: A low pass filter smooths a voltage corresponding to a least significant bit of a digital image signal outputted from an A/D convertor, and outputs the smoothed voltage to a sample-and-hold circuit. In the sample-and-hold circuit, a sample-hold-pulse is added during an optical black period, so that a voltage of the least significant bit of only a black level is extracted and outputted to a clamp level adjusting circuit. In the clamp level adjusting circuit, when the voltage inputted from the sample-and-hold circuit is higher 0 volts, a voltage, corresponding to a standard voltage from which the inputted voltage is subtracted by a differential amplifier, is outputted to a clamp circuit, and when the inputted voltage is 0 volts, the clamp voltage is pulled up by a pull-up resistance.

Abstract: In order to suppress variations in the set currents of a plurality of constant current circuits, there is provided a processing apparatus having a constant current supply unit including a plurality of constant current circuits, a plurality of sample/hold circuits for sampling/holding current values for maintaining currents supplied from the constant current circuits constant, and a constant current source for supplying a reference current for setting a current value to the plurality of sample/hold circuits.

Abstract: A signal processor circuit which stabilizes a clamp processing of black levels even in an endoscope system of an all-pixels readout type and prevents image qualities from being degraded at a stage to shift from a still image to a moving image in particular. In this signal processor circuit, video signals of all picture elements obtained with a single exposure are read out of a CCD, odd line data is stored into a first memory, even line data is stored into a second memory, and mixed picture element signals are generated by a mixer circuit, whereafter a predetermined image processing is performed by a first DVP. A clamp circuit and an A/D converter are disposed at stages preceding the first and second memories, a through video signal output from the A/D converter is input into the first DVP by way of a selector circuit on the basis of an optical black pulse and a black level clamp signal generated on the basis of the through video signal is fed back to the clamp circuit.

Abstract: An image data processing apparatus includes a controller which matches a dynamic range of image data to be outputted to an output unit to a dynamic range of data and/or to an output characteristic of the output unit so that the data may be processed in the output unit.

Abstract: An original image is encoded using difference signals that correspond to the difference between the original image and a blur image that approximates the original image. The blur image is generated using DC signals, wherein each DC signal corresponds to a different block of the original image.

Abstract: A method and apparatus for removing low frequency noise and any offsets common to a plurality of samples of a signal, for calibrating an offset level to be added to the signal to reference the signal to a desired reference level at an output of the apparatus, and for clamping an input voltage level to the apparatus to a desired voltage within an operating range of the apparatus. The apparatus includes a correlated double-sampling circuit which takes a first sample and a second sample of the analog signal, takes a difference between the first sample and the second sample to remove low frequency noise and any offsets common to both sample and which outputs a difference signal. In addition, the apparatus includes a black level correction circuit which adds an offset level to the difference signal to calibrate the offset level to be added to the difference signal so that the difference signal is at a desired reference level at an output of the apparatus.

Abstract: A solid state imager device such as a CCD imager device includes a timing generator which generates and supplies a clamping circuit with, a clamping pulse for clamping a first signal, corresponding to one pixel, from a through region of a CCD shift register, and a clamping pulse for clamping a second signal, corresponding to one pixel, from an optical black region of a sensor array. Specifically, the clamping pulse for clamping the first signal clamps a signal, corresponding to a first pixel, from the through region, and the clamping pulse for clamping the second signal clamps a signal, corresponding to a second or following pixel, from the optical black region. An output signal from the clamping circuit is supplied to an A/D converter which converts the supplied signal at such timing as not to sample the signal, corresponding to the first pixel, from the through region.

Abstract: An image-signal clamping circuit processes image signals obtained from a solid state image sensor provided at a distal end of an electronic endoscope which do not have a direct-current component to restore a direct-current component thereof. The clamping circuit is arranged such that the restoration of a direct-current component of an image signal can be properly and stably carried out. The clamping circuit includes a sample-and-hold circuit to temporarily store an image signal, an analog-to-digital converter to output digital image signals, a device for digitally correcting the digital image data, and a digital-to-analog converter to output corrected analog image signals. The pedestal level of the corrected output analog image signal approximates a reference pedestal level.

Abstract: A scanner having a photosensitive scanning array includes a timing generator having (a) a first state wherein pixel clock signals with a predetermined frequency are produced and (b) a second state wherein a D.C. restore clock signal with a frequency that is "N" times slower than the predetermined frequency is produced. The timing generator controls the rate of sampling the scanning array to acquire image data by producing a series of analog image signals containing (a) a video component which is characteristic of a density pattern of a scanned image and (b) a D.C. offset component which is characteristic of the scanning array. The timing generator also controls the rate of sampling the scanning array to acquire an analog signal containing only the D.C. offset component. A D.C. restore calculates an output signal containing only the video component of the series of analog image signals containing the video component and the D.C. offset component.

Abstract: A signal processing apparatus includes a first loop circuit for adjusting gains of a plurality of variable gain amplifiers to which signals output from a charge-coupled device (CCD) imager of multiple-channel reading type are applied, a control circuit for driving and controlling an iris in accordance with output signals from the plurality of variable gain amplifiers, a second loop circuit for adjusting levels of pilot signals to be superimposed upon the output signals of the CCD imager at a desired level, respectively, a third loop circuit for controlling levels of the pilot signals which are superimposed upon the output signals of the CCD imager so as to be coincident with each other, and a control unit for controlling the first loop circuit and the control circuit, the second loop circuit, and the third loop circuit so that they are operated in a time-division fashion.

Abstract: A solid-state image sensing apparatus comprises a charge coupled device, a plurality of photosensors, and a voltage generator. Each of the photosensors receives incident light, generates a voltage logarithmically proportional to an intensity of the incident light, and is connected to a first electrode of the charge coupled device. The voltage generator generates a reference voltage logarithmically proportional to an average intensity of the incident light on the photosensors and is connected to a second electrode of the charge coupled device. Signal charges are injected into the charge coupled device, depending on the voltage impressed on the first and second electrodes, so that a direct current component of an output of the charge coupled device is controlled.

Abstract: An image processing apparatus includes an analog image signal clamp and an A/D converter that converts the analog image signal into an m bit digital signal. The clamp is controlled in accordance with an n+1 (m>n) bit digital image signal converted by the A/D converter and an n bit digital image signal portion of the m bit digital image signal is processed.

Abstract: The present invention is directed to a system and method for compensating for offset and gain drift in a fast scan direction during an image forming process. To achieve compensation, the present invention samples a plurality of permanently darkened pixels upon powering up image sensors and circuitry therefor and during a sub-scanning process of an image and feeds this information into an offset value generating circuit. The offset generating circuit continually adjusts a pixel offset voltage according to a difference between sequential samples of the permanently darkened pixel, thereby compensating for fast scan offset drift. The present invention also samples a plurality of active pixels during a scanning of a calibration strip. From this scan, a gain corrective value is calculated. The present invention then samples active pixels during a scanning of a platen background.

Abstract: An object of this invention is to reduce level differences and errors in a luminance signal and color difference signals. In order to achieve the above object, an image pickup apparatus has an image sensor for photoelectrically converting an object image and a plurality of delay lines for delaying a video signal by one horizontal period, so that a video signal derived from an output including a clock leakage component from the image sensor is input to the plurality of delay lines, including an adjustment unit for adjusting the signal level of the video signal at an input or output of at least one of the plurality of delay lines.

Abstract: An automatic dark level zeroing circuit removes a dark level DC bias from an analog video signal generated by a charge-coupled device (CCD) camera, The automatic dark level zeroing circuit is DC-coupled to the CCD camera such that there is no loss of low frequency information in the analog video signal, The automatic dark level zeroing circuit forms an adaptive feedback loop that removes the dark level DC bias from the analog video signal by using a sampled value of the analog video signal that represents an internally masked pixel to produce a zero correction signal that is then combined with the analog video signal to remove the dark level DC bias without removing any useful video information or otherwise altering the information content of the analog video signal,

Abstract: A bipolar CCD signal processing circuit and method in which offset in a non-zero dark level of the CCD signal which is induced by pixel-to-pixel gain adjustment is compensated by applying a proportionate amount of the gain compensation component of the gain signal to the gain-adjusted CCD signal to compensate for the gain-induced offset whereby the dark level of the gain-adjusted CCD signal is substantially restored on a pixel-to-pixel basis to its predetermined non-zero value. When gain-induced offset compensation is employed, the range of any separately applied compensation for pixel-to-pixel offsets, other than those induced by gain compensation, is substantially reduced.

Abstract: An image sensing apparatus includes an image sensing circuit, an inverting circuit for inverting a polarity of an output of the image sensing circuit, and a correcting circuit for correcting a black reference level of the output of the image sensing circuit in accordance with an operation of the inversion circuit.

Abstract: In an image pick up device, signal level of red, green and blue color signals is coarsely adjusted in a signal processing circuit, and then a black level of video signal is finely adjusted in a digital signal processing circuit, thereby being capable of easily adjusting the black level and improving the accuracy of black level adjustment.

Abstract: A combined scene-based and DC-restored image restoration system enhances the utility of video images generated from the input of a forward-looking infrared system. This system and related methods remove a desired portion of the DC content from each of a plurality of input signals that are generated from a plurality of adjacent portions of a source image to obtain a plurality of resultant signals from which a plurality of video images is produced.

Abstract: A circuit is provided for correcting an image signal received from a camera wherein the camera includes a plurality of charge coupled devices, each for providing a light signal indicative of the intensity of light incident thereon and wherein the plurality of light signals from the plurality of charge coupled devices are indicative of an image received by the camera. The correction circuit includes a gain memory for storing a plurality of gain correction factors wherein each gain correction factor is associated with a respective charge coupled device of the camera. The correction circuit further includes an offset memory for storing a plurality of offset correction factors wherein each offset correction factor is associated with a respective one of the plurality of charged coupled devices. The gain memory is responsive to a control circuit for multiplying the plurality of electric signals by the appropriate gain correction factor.

Abstract: An automatic knee control circuit including a knee circuit for setting a knee point and a knee slope, a detecting circuit for detecting an output signal of the knee circuit and a comparing circuit for comparing an output of the detecting circuit with a reference voltage, wherein the knee circuit is controlled on the basis of an output of the comparing circuit. This automatic knee control circuit is characterized by a distributing circuit for distributing the output of the comparing circuit by an arbitrary distributing ratio, wherein the setting of the knee point is controlled by a first distributed output and the setting of the knee slope is controlled by a second distributed output, thereby making it possible to set a wide variety of signal processing states with ease. Therefore, pictures corresponding to cameraman's intention can be produced.

Abstract: A digital clamp circuit obtains a variation value of the black level varying per 1H period according to a predetermined clamp reference value, adds the variable value to an entire signal level to perform compensation of the variation of the black level, thereby enabling stable signal processing.

Abstract: There are disclosed electronic imaging systems employing CCD imaging units and one or more unique analog signal processors (ASP's). Each ASP receives color-component image signals from the CCD unit and provides respective output image signals, such as red, green and blue color components, having proper white balance for combining into a full color image. The dark background or zero level of the output image signals is referenced to a common "dark" reference voltage to minimize dark background variations in the combined color image regardless of the gain setting of the ASP or ASP's. Each ASP is substantially identical and has a unique architecture which facilitates its implementation as an integrated circuit. The ASP has a dynamic range of substantially better than 8-bits and provides for a wide range of signal sample rates (e.g., 1 to 40 MHz).

Abstract: A color video camera having an automatic white balance adjusting function and operating with selection of modes including a negative-to-positive reversal mode of shooting the color negative film to obtain the positive picture, wherein in the negative-to-positive reversal mode, the color signals output from the image sensor are amplified by the amplifiers whose gains have been changed from the values for an ordinary object shooting mode to values suited for shooting the negative film.

Abstract: A video camera apparatus having a solid state imager for generating video signals and a black level balance adjusting circuit for automatically adjusting black levels of the video signals. The video camera apparatus comprises an incident light control device, an electronic shutter control circuit, a comparator and a processor. The incident light control device controls the amount of light incident to the solid state imager. The electronic shutter control circuit varies the mode of the solid state imager between at least a first mode and a second mode. The effective accumulating period of the solid state imager in the first mode is different from the corresponding period in the second mode. The comparator compares the voltage level of the video signal obtained in the first mode with that obtained in the second mode.