Abstract: An insulated foot pad for a tripod has an insulated block sandwiched between two plates. The plates are made of a material that is a poor conductor of heat. Tripod legs placed on the foot pads will not sink into the snow on sunny days nor into warm asphalt on hot days.

Abstract: An Engineer's View (EV) wireless video system for powered and unpowered model railroad engines is disclosed. The invention uses commercially available wireless spy cameras, powered by a custom power supply circuit which is compatible with either DC or DCC track systems. The present invention is compatible with all commercial model railroad gauge diesel engines including HO and N Gauge or may be factory installed. The EV system demonstrates a remarkably stable and realistic image of a model railroad layout. Moreover, the present invention may also provide a stable source of power to the engine where stalling could occur at points of track defects.

Abstract: A display apparatus includes a signal input unit through which an image signal is input, the image signal comprising a synchronization signal and an active signal; an adjustment signal generating unit that generates an adjustment signal; a signal processing unit that receives the adjustment signal and adjusts the image signal based on the received adjustment signal; and a controller which analyzes the input signal and controls the adjustment signal generating unit to change characteristics of the adjustment signal if the adjustment signal does not lie within a blanking interval between the synchronization signal and the active signal. With this configuration, even when an image signal having a reduced blanking interval between the synchronization signal and the active signal is input, the adjustment signal can be generated within the blanking interval of the image signal, not within the active signal interval.

Abstract: Average picture level (APL) of a display and, in examples, histogram information is used to dynamically adjust the display contrast, or “gamma”, using an exponential function. APL can also be used for DC transmission adjustment and black/white stretch.

Abstract: An automatic clamping analog-to-digital converter (A/D converter) is provided, which includes an A/D converter, a switch, a comparator, a bidirectional counter, and a digital-to-analog converter (D/A converter). Wherein, the A/D converter receives an analog signal from a node, and then converts the analog signal into a digital signal according to a DC offset level. The switch is coupled between the node and a fixed voltage level, and is turned on or off according to a clamping signal. The comparator outputs a compare signal according to a comparison result between the digital signal and an offset value. The bidirectional counter outputs a count, and increases or decreases the count according to the compare signal. The D/A converter converts the count into the DC offset level and provides the DC offset level to the A/D converter.

Abstract: In a conventional contrast adjustment circuit, since an entire signal level of a luminance signal is shifted, peak luminance is lowered, and luminance deterioration is undesirably raised. In the present invention, a direct-current component of a luminance signal is shifted according to need, and a predetermined expansion processing to increase a signal level of highlight portion is performed for a luminance signal having its direct-current component shifted.

Abstract: A level clamping control circuit and associated level clamping control method are provided. The level clamping control circuit includes a reference level estimator, a subtractor, a clamping computation circuit, a dithering circuit, and a digital-to-analog converter (DAC). The reference level estimator estimates a reference level of the input signal. The subtractor computes a difference between the reference level and a desired reference level to output a difference signal. The clamping computation circuit generates a first control value according to the difference signal. The dithering circuit dithers the first control value to alternately output a plurality of second control values. Finally, the DAC respectively utilizes the second control values to charge or discharge a capacitor to adjust the reference level of the input signal.

Abstract: An adaptive Gamma voltage switching method and a device using the same is presented. An equalization unit utilizes a video data to obtain an equalized luminance data. An adaptive Gamma voltage switching core dynamically adjusts a Gamma voltage and outputs the adjusted Gamma voltage to a panel according to the equalized luminance data so as to enable the panel to alternately display a black insertion frame and a dynamic frame with adaptive contrast. The present invention not only enhances frame contrast but also reduces frame blur, and furthermore improves the insufficient luminance caused by black insertion.

Abstract: A video decoder in which 1) resolution quality can be improved for a given bit count analog-to-digital converter, 2) a lower bit count analog-to-digital converter can be used with substantially similar quality or 3) a combination of improved resolution quality with a lower bit count analog-to-digital converter can be done. In the preferred embodiment, a DC bias is added to the video signal after the sync portion of the composite signal has been received and prior to the active video being received. This bias is then removed after the end of the active video period. By applying this bias, the DC voltage level of the video signals is actually reduced, so that the full scale value of the analog-to-digital conversion process can also be reduced. Thus, compared to using an unbiased signal, increased A/D converter resolution is obtained. In an alternative embodiment, the sync portion can be biased upwardly during the front porch and then be returned during the back porch.

Abstract: Digital dc restore methods and apparatus to restore the DC component of an analog waveform to a quantized reference value level at a given temporal point on a waveform, prior to an ADC. This may used to establish the relationship between the full scale digital value out of the ADC and the waveform being digitized. For a video signal, the Digital Value of Black, is compared with the value on the back porch of the video signal. The difference is converted to the analog domain by a DAC clocked at the Temporal Point to provide a sample and hold function. An amplifier compares the difference, mapped to one half full scale digital, to an analog common mode voltage for the ADC, removing any error due to the difference between them. Other applications include correlated double sampling of contact image sensors to remove Dark Current Offset.

Abstract: An apparatus, system and method for clamping a video signal input to a coupling capacitor (215) for providing a clamping voltage. A charging current is applied to the capacitor (215) via an amplifier (225) having a first input (227) coupled with the capacitor output and a second input (226) coupled to a reference potential, the amplifier (225) is responsive to the capacitor output signal and the reference potential for providing the charging current to the capacitor (215). The current has a linearly varying magnitude which is proportional to a difference between the capacitor output and the reference potential.

Abstract: A method and apparatus for adjusting the amplitude and DC bias of a video signal is presented, which may be performed in preparation for analog-to-digital conversion. This is accomplished by first converting a received voltage mode video signal to a current mode video signal. Similarly, a voltage mode bias control signal is converted to a current mode bias control signal. The amplitude of the current mode video signal is then adjusted to produce an amplitude adjusted video signal. Similarly, the amplitude of the current mode bias signal is adjusted to produce an amplitude adjusted bias control signal. The current mode amplitude adjusted signals are then combined to produce a biased adjusted current mode video signal. The biased adjusted current mode video signal is then converted back to a voltage mode signal, which may be provided to an analog-to-digital converter for conversion.

Abstract: A clamping circuit for supplying a clamped color signal to a gamma-correction circuit is provided with a clamping portion connected to a clamping voltage generating circuit. The clamping voltage generating circuit generates a clamping voltage in response to an individual control signal in such a way that the black level of a color signal coincides with the black level in an input/output characteristic of the gamma-correction circuit. The clamping portion adds this clamping voltage to the pedestal level of a color signal at a predetermined timing in response to a control signal, so as to absorb variations in black levels of the clamping levels and later-stage circuits including variation in the later-stage circuits.

Abstract: An appropriate correction quantity is obtained for a video luminance signal on an individual video basis with a characteristic value, like the maximum or average value, of the luminance signal taken into account, thereby performing gray scale correction more effectively.

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: An illumination intensity correcting circuit including a curve fitting circuit formed by differential amplifier circuits and a load resistor, wherein the amplification factor of the curve fitting circuit is changed before and after each breakpoint voltage, the reference voltages of the differential amplifier circuits are set so that at least two breakpoint voltages are arranged in the range of a voltage of a video signal, and the amplification factors of the differential amplifier circuits are set so that the amplification factor of the curve fitting circuit in the range of the signal voltage inside of the two breakpoint voltages is smaller than the amplification factor outside of the two breakpoint voltages.

Abstract: A video camera and imaging system having signal processing circuitry configured to change the black level (pedestal) of a video signal in response to comparing an overall system gain (for instance, a gain value and the electronic exposure time of the image sensor) to a threshold value. The change helps to automatically obtain brighter and more detailed images, particularly with imaging systems which are optimized for intraoral (dental) imaging but are also used to capture a headshot of the patent's smile or face.

Abstract: A gamma correction circuit includes an amplifier (A) coupled to receive an input signal (Vi), and a non-linear impedance (Rg) coupled to the amplifier (A) for determining a gain of the gamma correction circuit in such a manner that the gain increases when the input signal (Vi) increases.

Abstract: The present invention provides a method, a device, and a system for performing gamma correction on a set of pixel data based on a gamma correction curve table. The gamma correction curve table includes a specified total number of intensity levels associated with gamma corrected pixel values with one intensity level per pixel value. The method includes partitioning the gamma correction curve table into N segments such that each of the N segments is associated with a set of intensity levels from the specified total number of intensity levels. A plurality of intensity levels is selected for each of the N segments such that significant banding effects are not visible to the human eye between an adjacent pair of the selected intensity levels. The gamma corrected pixel values are stored for each of the N segments such that each of the plurality of selected intensity levels functions as an index to the associated gamma corrected pixel values.

Abstract: An illumination intensity correcting circuit including a curve fitting circuit formed by differential amplifier circuits and a load resistor, wherein the amplification factor of the curve fitting circuit is changed before and after each breakpoint voltage, the reference voltages of the differential amplifier circuits are set so that at least two breakpoint voltages are arranged in the range of a voltage of a video signal, and the amplification factors of the differential amplifier circuits are set so that the amplification factor of the curve fitting circuit in the range of the signal voltage inside of the two breakpoint voltages is smaller than the amplification factor outside of the two breakpoint voltages.

Abstract: A video signal processing circuit in which nearly 100% of a largest possible dynamic range can be used, desired contrast is obtained, and desired brightness characteristics are obtained by an increasing in luminance of a screen. The circuit has an RGB amplifier which amplifies three primary color video signals R, G, and B by a predetermined gain and in which the gain is controlled by a gain control signal, A/D converters for converting analog three primary color video signals which are generated from the RGB amplifier into digital signals respectively, inverse gamma correcting circuits for effecting an inverse gamma correction to the three primary color digital video signals respectively, an OR circuit and a peak holding circuit for detecting peak levels of the analog three primary color signals, and a gain control signal generator for generating a gain control signal in accordance with the peak levels.

Abstract: Aiming to improve color reproducibility of a red part having high color saturation, a gamma compensation apparatus of the present invention is composed of a bending point setting block 100a and a gamma compensation block 101a and bending point setting block 100a is composed of a high APL detection circuit 1a inputting an average picture level of an input luminance signal and for detecting and taking out a signal component higher than a designated level; a gain controller 2a for gain controlling the detected signal at the high APL picture detection circuit; and an adder 3a for adding a designated offset to the output of gain controller 2a, and gamma compensation block 101a is composed of a slice circuit 4a inputting a color difference signal (R-Y) and the output of bending point setting block 100a and taking out a color difference signal component higher than the output signal level of bending point setting block 100a; a gain controller 5a for adjusting the output level of slice circuit 4a; and a subtracter 6a

Abstract: A non-linear response correction apparatus and method reduce look up table size and output error. In one embodiment, a range of an N-bit input signal is split into two or more sectors, based on a gradient of a non-linear correction curve and an allowable error, and then a N-bit input signal is divided into U upper bits and D lower bits where U and D depend on which sector contains the input signal. First and second look up tables read first and second data stored therein, respectively, using the upper bits of the digital signal as an address. The first data is the difference between a corrected signal and the input signal, and the second data is the gradient of the corrected signal with respect to the gradient of the input signal. The second data read from the second look up table is multiplied by the lower bits, and the first data read from the first look up table is added to the upper bits.

Abstract: A gamma correction circuit is provided for gamma correcting first and second polarity video signals of different polarity. The gamma correction circuit includes first and second resistance elements R1, R2 connected in series between a power supply terminal 50 and a ground terminal 52 and a third resistance element R3 connected in parallel with the first resistance element R1 between the power supply terminal 50 and the second resistance element R2. A fourth resistance element R4 is connected in parallel with the second resistance element R2 between the ground terminal 52 and the third resistance element R3. An output terminal 54 is arranged between the first and second resistance elements R1, R2. An input transistor Tr1 is connected between the first and second resistance elements R1, R2 with its base supplied with a video signal. A first control transistor is connected between the power supply terminal 50 and the third resistance element R3.

Abstract: A clamp and gamma correction circuit which processes an image signal through a clamp circuit and then a gamma correction circuit in that order to perform a proper gamma correction with a clamp voltage adjusted to its appropriate value. An image signal varying between a black level and a white level is applied to the clamp circuit. The clamp circuit outputs an image signal, the black level of which is clamped to the clamp voltage, while the amplitude between the black level and the white level is maintained at constant level. The gamma correction circuit amplifies the image signal output by the clamp circuit at different amplification factors based on a reference voltage. A voltage setting circuit varies the clamp voltage and the reference voltage but with the voltage difference therebetween kept constant, and applies the clamp voltage and the reference voltage to the clamp circuit and the gamma correction circuit, respectively.

Abstract: In a projection type image display apparatus, the screen is divided and a memory to record luminance correction data corresponding to the divided regions is provided, and addresses of the divided regions of the screen are set by an address counter, synchronized with the input video signal. The luminance correction data are read successively by inputting the addresses to the memory, and luminance nonuniformity on the screen is corrected through operational processing of the correction value converted in an analog value by a D/A converter and the input video signal. The luminance correction data is obtained by computing measurement results of respective luminance characteristics of red, green, and blue colors on the screen and separately recorded as an amplitude correction component and a DC level correction component.

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: The direct current voltage level and amplification of a multiple channel output imaging element are adjusted by comparing the output values of each channel. A calculating device, such as, for example, a CPU uses the data of one channel (i.e., a standard channel), which was sampled by a sampling circuit, as a standard, and then takes the difference between this data and the data of the other channels to calculate the offset and amplification differences. The results are sent to a D/A unit, which sends regulating voltages to offset regulating circuits and to amplifying circuits. In this manner, the offsets and amplifications of each channel are adjusted so as to become equal.

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 video processor, having an input and an output, for compensating for accumulated phase and amplitude errors encountered during transmission of a video signal over a communications channel. The video processor includes a high-pass filter and amplifier, coupled to the input; a post-correction-phase-and-gain restorer; a wide-band-video-delay line coupled to the input; a pre-correction-comb-equalizer restorer; and a combining network, coupled to the output. The high-pass filter has a bandwidth characteristic which is approximately inverse to a low-pass characteristic encountered by the video signal during its transmission over the communications channel. The high-pass filter takes the video signal and outputs a filtered-video signal. The amplifier associated with the high-pass filter inverts the filtered-video signal. The post-correction-phase-and-gain restorer adjusts the inverted-filtered-video signal to generate a restored-video signal.

Abstract: A contour restoration circuit comprises an input terminal, a plural of delay circuits connected to the input terminal in series, a maximum value detection circuit, a minimum value detection circuit, a mean value calculating the mean value from the maximum and minimum values, a subtractor for subtracting the mean value from the input video signal, a gain controller for the subtracted signal, an adder for adding the gain controlled signal to the input video signal and an output terminal.

Abstract: A display unit in which a black level is set to a predetermined level in a first display screen having a first aspect ratio and a black level is set to a predetermined level in a second display screen having a second aspect ratio is provided. A darkest signal of a video signal is detected from an image area corresponding to the second display screen. The darkest signal is lowered to a predetermined level in an image area corresponding to the first display screen. In accordance with the principles of the present invention, the situation where a video signal of the second display screen that is to be lowered will not be lowered can be prevented.

Abstract: A video processor, having an input and an output, for compensating for accumulated phase and amplitude errors encountered during transmission of a video signal over a communications channel. The video processor includes a high-pass filter and amplifier, coupled to the input; a post-correction-phase-and-gain restorer; a wide-band-video-delay line coupled to the input; a pre-correction-gain restorer; and a combining network, coupled to the output. The high-pass filter has a bandwidth characteristic which is approximately inverse to a low-pass characteristic encountered by the video signal during its transmission over the communications channel. The high-pass filter takes the video signal and outputs a filtered-video signal. The amplifier associated with the high-pass filter inverts the filtered-video signal. The post-correction-phase-and-gain restorer adjusts the inverted-filtered-video signal to generate a restored-video signal.

Abstract: A gamma-compensating circuit has a voltage amplifying unit for amplifying a gamma-compensated picture signal from a broadcasting station and a nonlinear-compensation unit for converting an output amplification degree of the voltage amplifying unit to linearize the amplified gamma-compensated picture signal in accordance with a voltage level of the gamma-compensated picture signal. A linearized amplified gamma-compensated picture signal is obtained from the gamma-compensated picture signal transmitted from a broadcasting station.

Abstract: An image signal sent from an image sensor is input to the inverting terminal of a differential amplifier. An A/D converter converts an output of the differential amplifier to digital output data. A comparison circuit compares the digital output data with a reference value in a dummy bit period to produce a comparison result, for instance, a difference between the digital output data and the reference value. Based on the comparison result, a correction value setting circuit modifies a correction value so that a DC offset becomes closer to the reference value. For example, the correction value setting circuit adds the difference obtained by the comparison circuit to the correction value. A D/A converter converts the modified correction data to an analog voltage, which is input to the noninverting terminal of the differential amplifier.