US 4,786,818 A · Integrated sensor and processor for visual images

Abstract

An integrated sensor and analog processor for visual images is produced from an array of photoreceptor signals that are the space-time derivative of the photoreceptor outputs. Each photoreceptor output V.sub.R is first processed by an integrator having a predetermined time constant using a differential transconductance amplifier driving an integrating capacitor, and feeding the output signals V.sub.H back to the negative input, thereby generating a time integrated signal for each pixel of the array. The output terminal of the integrating amplifier is connected to a node that is coupled to the outputs of similar integrators of neighboring pixels by resistive connections thereby forming a spatially smoothed version of the image. At each node a differential amplifier takes the difference between the node potential and local receptor potential, whereby an output representing a first temporal derivative and second spatial derivative is computed.

Claims13

Dependent claims

An analog circuit for simultaneously computing the space-time average of a plurality of signals at inputs to an array comprising

a plurality of nodes, each having capacitance connected to a source of fixed potential,
a network of resistive connections between said plurality of nodes in said array,
a separate integrator associated with each of said signal inputs, and
means for injecting a current into each node of said array through said separate integrator associated therewith such that the magnitude of said current is an odd, monotonically increasing function of the potential difference between one of said signal inputs and said node.

1 more element

A CMOS analog integrated circuit for simultaneously computing the space-time average of a plurality of signal inputs comprising

a plurality of nodes in an array,
a network of resistive connections, one resistive connection between each pair of adjacent nodes in said array, each node having a capacitance to a source of fixed potential,
each resistive connection between a pair of nodes of said network comprising an MOS transistor circuit, the current flowing through said circuit when the potential difference is zero between said nodes being no larger than the leakage current of the MOS transistors in said circuit, and said current being a monotonically increasing function of the potential difference between said nodes, and
means for injecting current into each node of said array such that the magnitude of said current is a monotonically increasing function of the potential difference between a separate one of said signal inputs and said node.

1 more element

An array of resistive connections in an analog circuit for simultaneously computing the space-time average of a plurality of input signals comprising

a plurality of nodes, said adjacent ones of said nodes being connected together by separate ones of said resistive connections, each resistive connection having one end connected to one of said nodes and its other end connected to an adjacent node, each analog circuit having a separate means for producing a signal input, and each node having a capacitance connected to a source of fixed potential, each of said means for producing a signal input serving to inject a current into a separate node of said array such that the magnitude of said current is an odd, monotonically increasing function of the potential difference between one of said signal inputs and said node.

Dependencies are inferred from the claim text.

Integrated sensor and processor for visual images

Life of this patent

Integrated sensor and processor for visual images

Life of this patent

Abstract

Claims13