Digitally active distance measurement apparatus for camera or the like

A distance measurement apparatus comprising:

• projecting means for projecting an infrared-ray on a distance measurement object;
• light-receiving means for receiving light reflected by the distance measurement object upon projection of the infrared-ray on the distance measurement object, and outputting a photocurrent corresponding to an irradiated position of the light and an ordinary photocurrent;
• first A/D converting means for detecting the ordinary photocurrent output from said light-receiving means prior to a projection operation by said projecting means, and converting a detected ordinary photocurrent into a digital signal;
• first digital memory means for storing the digital signal converted by said first A/D converting means;
• current extracting means for extracting a current component corresponding to a storage value of said first digital memory means from the photocurrents output by said light-receiving means during the projection operation;
• analog arithmetic means for outputting an analog distance signal corresponding to a distance to the distance measurement object, using an output current from said light receiving means upon processing by said current extracting means;
• second A/D converting means for converting the analog distance signal into a digital distance signal;
• and
• second digital memory means for storing an output from said second A/D converting means.

A distance measurement apparatus comprising:

• projecting means for repeatedly projecting light on a distance measurement object;
• light-receiving means for receiving light reflected by the distance measurement object upon projection of the light on the distance measurement object and outputting a photocurrent containing an ordinary photocurrent component;
• ordinary photocurrent extracting means for storing the photocurrent as the ordinary photocurrent component output by said light-receiving means during non-projection of said projecting means, extracting the ordinary photocurrent component from the photocurrent during projection of said projection means by using a storage value, and outputting a signal corresponding to the projection, the ordinary photocurrent component being digitally stored;
• arithmetic means for calculating an analog object distance using the signal output by said ordinary photocurrent extracting means;
• and
• accumulating means for accumulating outputs from said arithmetic means in accordance with repeated projection by said projecting means and outputting an average object distance of all projection operations, said accumulating means converting an analog output from said arithmetic means into digital data, and accumulating converted digital values.

A distance measurement apparatus comprising:

• projecting means for projecting a beam toward an object;
• light-receiving means for receiving light reflected by the object upon incidence of the beam thereon and outputting a photocurrent signal containing an ordinary photocurrent component;
• analog-to-digital converting means for performing analog-to-digital conversion of the photocurrent signal as the ordinary photocurrent component output by said light-receiving means during non-projection of said projecting means;
• memory means for storing a digital value of the ordinary photocurrent component converted by said digital-to-analog converting means;
• current extracting means for extracting the ordinary photocurrent component from the photocurrent signal output by said light-receiving means during projection of said projecting means on the basis of the digital value stored in said memory means;
• and
• arithmetic means for calculating a distance to the object using an output current from said light-receiving means from which the ordinary photocurrent component is extracted by said current extracting means.

An active distance measurement apparatus comprising:

• an infrared-emitting diode for projecting an infrared-ray on a distance measurement object through a projection lens;
• an optical position detecting element for receiving, through a light-receiving lens, light reflected by the distance measurement object upon projection of the infrared-ray on the distance measurement object, and outputting a photocurrent corresponding to an irradiated position and an ordinary photocurrent;
• an A/D converter for detecting the ordinary photocurrent output by said optical position detecting element prior to a projection operation by said infrared-emitting diode, and converting the ordinary photocurrent into a digital signal;
• a digital memory circuit for storing the digital signal converted by said A/D converter;
• a current extraction circuit for extracting a current corresponding to a storage value of said digital memory circuit from the photocurrents output by said optical position detecting element during the projection operation;
• and
• an arithmetic circuit for outputting a signal corresponding to a distance to the distance measurement object, using an output from said optical position detecting element from which the current is extracted by said current extraction circuit.

An active distance measurement apparatus comprising:

• projecting means for projecting an infrared-ray on a distance measurement object through a projection lens;
• means for receiving, through a light-receiving lens, light reflected by the distance measurement object upon projection of the infrared-ray on the distance measurement object, and outputting a photocurrent corresponding to an irradiated position and an ordinary photocurrent;
• means for storing the ordinary photocurrent output by said light-receiving means as a digital signal prior to a projection operation by said projecting means;
• means for extracting a current corresponding to a storage value of said storing means from the photocurrents output by said light-receiving means during the projection operation;
• and
• means for calculating a distance to the distance measurement object, using an output from said light-receiving means from which the current is extracted by said extracting means.

A distance measurement apparatus comprising:

• projecting means for projecting a beam toward an object;
• light-receiving means for receiving light reflected by the object upon projection of the beam on the object and outputting a photocurrent signal containing an ordinary photocurrent component;
• a flip-flop group, a digital output of which a value is sequentially changed in synchronism with a clock pulse;
• digital-to-analog converting means for converting the digital output from said flip-flop group into an analog current having a value corresponding to the value of the digital output, and extracting the analog current from the photocurrent signal output by said light-receiving means;
• voltage transforming means for converting the analog current output by said digital-to analog converting means into a voltage signal;
• comparing means for comparing the voltage signal converted by said voltage transforming means with a reference voltage;
• digital memory means for storing a comparison result from said comparing means in association with a change in the value of the digital output by said flip-flop group in a state prior to projection by said projecting means, thereby storing the ordinary current component as a digital value;
• and
• arithmetic means for extracting the ordinary photocurrent component from the photocurrent signal output by said light-receiving means on the basis of the digital value stored in said digital memory means during projection of the beam by said projecting means, and calculating a distance to the object using a signal current component obtained in an extracting operation.

A distance measurement apparatus comprising:

• projecting means for projecting light on an object;
• light-receiving means for receiving light reflected by the object upon projection of the light on the object, and outputting a photocurrent signal containing an ordinary photocurrent component;
• ordinary photocurrent extracting means for storing the photocurrent signal as the ordinary photocurrent component output by said light-receiving means in non-projection of said projecting means, extracting the ordinary photocurrent component from the photocurrent signal in projection of said projecting means, using a storage value, and outputting a signal corresponding to projection, the ordinary photocurrent component being stored as a digital value;
• and
• arithmetic means for calculating an object distance using the signal output by said ordinary photocurrent extracting means.

A distance measurement apparatus comprising:

• projecting means for projecting distance measurement light on an object;
• and
• light-receiving means for receiving light reflected by the object upon projection of the distance measurement light on the object to obtain a distance signal corresponding to a distance to the object, said light-receiving means including:
• (a) means for detecting an ordinary light component contained in the reflected light in advance, and storing the ordinary light component in the form of a digital signal;
• and
• (b) means for eliminating the ordinary light component from an output from said light-receiving means on the basis of a storage value in said memory means during projection by said projecting means.

A distance measurement apparatus for a camera, comprising:

• an infrared-emitting diode for projecting an infrared-ray on a distance measurement object;
• an optical position detection element for receiving light reflected by the distance measurement object upon incidence of the infrared-ray thereon, and outputting a photocurrent corresponding to an irradiated position;
• an analog arithmetic circuit for outputting an analog distance signal corresponding to a distance to the distance measurement object, using an output from said optical position detection element;
• an A/D converter for converting the analog distance signal into a digital distance signal;
• a control circuit for operating said infrared-emitting diode, said optical position detection element, and said analog arithmetic circuit so as to perform distance measurement operations a plurality of number of times;
• a memory circuit in which latest outputs from said A/D converter are sequentially added and accumulated whenever each of the distance measurement operations performed the plurality of number of times is performed;
• and
• a processing circuit for performing digital processing corresponding to arithmetic averaging of data accumulated in said memory circuit upon completion of the distance measurement operations performed the plurality of number of times.

A distance measurement apparatus comprising:

• projecting means for repeatedly projecting a beam toward an object;
• light-receiving means for receiving light components reflected by the object upon repeated projection of the beam, and outputting a photocurrent signal;
• arithmetic means for outputting an analog current signal corresponding to a distance to the object, on the basis of a signal corresponding to the photocurrent signal output by said light-receiving means;
• a flip-flop group, a digital output of which a value is sequentially changed in synchronism with a clock pulse;
• digital-to-analog converting means for generating an analog converted current corresponding to the value of the digital output from said flip-flop group, and extracting the analog converted current from the analog current signal output by said arithmetic means;
• voltage transforming means for generating a voltage signal corresponding to the analog converted current output by said digital-to-analog converting means;
• comparing means for comparing the voltage signal from said voltage transforming means with a reference voltage;
• digital memory means for storing a comparison result from said comparing means in association with a change in the value of the digital output from said flip-flop group, thereby storing a digital value corresponding to the analog current signal output by said arithmetic means;
• and
• accumulating means for adding the digital value stored in said memory means in accordance with the repeated projection by said projecting means to output an accumulated value of outputs from said arithmetic means upon completion of all projection operations.

An active distance measuring means comprising:

• (a) projecting means for projecting an infrared-ray on a distance measurement object;
• (b) light-receiving means for receiving light reflected by the distance measurement object upon radiation of the infrared-ray on the distance measurement object, and outputting an analog signal corresponding to a distance to the distance measurement object;
• (c) converting means for converting the analog signal output by said light-receiving means into a digital signal;
• (d) control means for operating said projecting means, said light-receiving means, and said converting means a plurality of number of times;
• (e) memory means in which latest digital outputs from said converting means are sequentially added and accumulated whenever the plurality of number of times is performed;
• and
• (f) arithmetic means for performing arithmetic operations corresponding to arithmetic averaging of the data stored in said memory means.

An active distance measurement apparatus comprising:

• (a) projecting means for projecting distance measurement light on an object a plurality of number of times;
• (b) light-receiving means for receiving light reflected by the object whenever each of projection operations performed the plurality of number of times is performed and outputting digital data corresponding to a distance to the object;
• and
• (c) arithmetic means for adding and accumulating a plurality of digital data from said light-receiving means and obtaining a final object distance on the basis of an accumulation content.

A distance measurement apparatus comprising:

• projecting means for repeatedly projecting a pulsed light on an object;
• light-receiving means for receiving light reflected by the object upon projection of the pulsed light on the object and outputting a photoelectric signal;
• arithmetic means for calculating a distance to the object, using a value corresponding to the photoelectric signal output by said light-receiving means;
• and
• accumulating means for accumulating outputs from said arithmetic means in accordance with repeated projection by said projecting means, said accumulating means converting an output from said arithmetic means into a digital value, and accumulating a converted digital value.

An active distance measurement system comprising:

• projecting means for projecting distance measurement light on an object;
• and
• light-receiving means for receiving light reflected by the object and outputting object distance data, said light-receiving means being constituted by a one-chip IC and including at least:
• (a) a light-receiving element for receiving the reflected light from the object;
• (b) an analog arithmetic circuit for outputting an analog distance signal corresponding to a distance to the object in accordance with an output from said light-receiving element;
• (c) an A/D converter for converting the analog distance signal from said analog arithmetic circuit into a digital distance signal;
• and
• (d) a transfer circuit and a terminal for transferring the digital distance signal from said A/D converter to an external processing circuit.