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AssigneeHonda Giken Kogyo Kabushiki Kaisha
InventorsMakoto Furukawa, Sukeyuki Shinotsuka, Jiro Kurita, Katsuhiko Takebe
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An output compensating device capable of optimally compensating output signals of an image sensor composed of a number of light-sensor circuits, each of which represents a unit pixel and is capable of producing in a photoelectric converting element a sensor current proportional to a quantity of light falling thereon, converting the current into a voltage signal by a MOS type transistor with a logarithmic output characteristic in a weak inverse state, initializing itself by removing a charge accumulated in a parasitic capacitor of the photoelectric converting element by changing a drain voltage of the transistor to a value lower than a normal value for a specified time and outputting a pixel signal having a logarithmic characteristic at a large quantity of the sensor current and a pixel signal having a non-logarithmic characteristic at a small quantity of the sensor current. This device has a means for compensating each pixel signal from the image sensor for an offset value and outputting a resulting signal if said signal has an output characteristic within a logarithmic response region or a non-logarithmic region depending on the output condition and, if not, further compensating the offset-compensated signal for its gain and outputting a resulting signal, thus ensuring the optimal compensation of each pixel signal of the image sensor in accordance with its output state.
An output compensating device for an image sensor composed of a number of light sensor circuits arranged to form a matrix of pixels, each circuit representing a unit pixel and capable of producing in a photoelectric converting element a sensor current proportional to a quantity of light falling thereon and converting the current into a voltage signal by a MOS type transistor with a logarithmic output characteristic in a weak inverse state, wherein an image sensor body capable of reading each pixel signal through a means provided for reading a compensation value from a memory storing a table of compensation values predetermined for variations in output characteristics of respective pixel signals and executing arithmetic operations for compensating the pixel signal by using an arithmetic calculation circuit and the compensation value taken from the memory is mounted on a single chip or substrate in a package with the memory and the arithmetic circuit disposed therein.
An output-compensating device for an image sensor capable of reading pixel signals from each of MOS type light-sensor circuits each provided at its output side with a variable bias voltage applied thereto through a reference resistance, which has a means for adjusting the bias voltage in accordance with a temperature of the image sensor detected by a temperature sensor.
An output compensating method for an image sensor composed of a number of light sensor circuits each representing a unit pixel and capable of producing in a photoelectric converting element a sensor current proportional to a quantity of light falling thereon and converting the current into a voltage signal by a MOS type transistor and is provided with a means for outputting a pixel signal having a logarithmic characteristic at a large quantity of the sensor current and a pixel signal having a non-logarithmic characteristic at a small quantity of the sensor current, the method comprising the steps of executing offset compensation of each pixel signal from the image sensor and outputting a resultant signal if said signal has an output characteristic only within a logarithmic response region and, if said signal has an output in a non-logarithmic response region, then further executing a gain compensation of said signal and then outputting a resultant signal.
Dependencies are inferred from the claim text.