Solid state imaging apparatus with means for controlling signal accumulation period

• US 4,819,075 A
• Filed: 09/23/1987
• Issued: 04/04/1989
• Est. Priority Date: 09/24/1986
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Noda, Masaru, Nishimura, Ryuji, Imaide, Takuya
• Primary Examiner(s): Lev, Robert
• Application Number:
  US07/100,233
• Time in Patent Office: 559 Days
• Field of Search: 358/211, 358/213.18, 358/213.25, 358/213.19, 358/217, 358/219
• US Class Current: 348/297
• CPC Class Codes: H04N 23/70 Circuitry for compensating brightness variation in the scene
• CPC Class Codes: H04N 23/73 by influencing the exposure time

Abstract

In an apparatus reading out picture data from an imaging device to store the data once in a memory and reading out the data again from the memory so that the video signal may be processed for reproduction, the period during which the picture data is read out from the imaging device is regulated to be varied according to luminance of an object, and to be longer than a field period, whereby a good reproduced picture with reduced noise is obtained.

Claims

1. In a solid state imaging apparatus having photoelectric conversion means consisting of an array of plural photoelectric conversion devices disposed in two dimensions for converting optical information into analog electrical picture element data and means for digitizing the picture element data obtained by said array of photoelectric conversion devices and sequentially reading out the digitized picture element data;

and an output circuit to which the picture element data is input and from which a picture signal is output;

said solid state imaging apparatus comprising;

a first field memory having a capacity for storing digitized picture element data for one field;

a second field memory having a capacity for storing digitized picture element data for one field;

a first line memory having a capacity for storing digitized picture element data for one line;

a second line memory having a capacity for storing digitized picture element data for one line;

first switching means, during a period m times the horizontal scanning period, supplying digitized picture element data obtained from said photoelectric conversion means to said first line memory and, during another period of one horizontal scanning period, supplying the picture element data stored in said first line memory to said first field memory;

second switching means, during a period m times the horizontal scanning period, supplying digitized picture element data obtained from said photoelectric conversion means to said second line memory and, during another period of one horizontal scanning period, supplying the picture element data stored in said second line memory to said second field memory;

third switching means for connecting said first and second field memories alternately to said output circuit;

first signal generator means for generating a control signal for setting the accumulation period on said array of photoelectric conversion devices to m (m>

1) times the field period and supplying this signal to said photoelectric conversion means and also generating write addresses for said first and second field memories;

second signal generator means for generating read addresses for reading out digitized picture element data from said first and second field memories at intervals of one horizontal scanning period; and

fourth switching means for supplying the read addresses generated by said second signal generator means to said first and second field memories alternately at intervals of one horizontal scanning period and also supplying the write address generated by said first signal generator means to said first or second field memory during a certain horizontal scanning period, wherein

said photoelectric conversion means outputs digitized picture element data for one line during a period m times the horizontal scanning period according to the control signal supplied from said first signal generator means, and during a certain period m times the horizontal scanning period, the digitized picture element data output from said photoelectric conversion means is written in said first line memory during the period m times the horizontal scanning period, picture element data stored in said second line memory is read out and written in said second field memory, and picture element data stored in said first and second field memories are supplied to said output circuit alternately at intervals of one horizontal scanning period, whereas, during another period m times the horizontal scanning period, the digitized picture element data output from said photoelectric conversion means is written in said second line memory during the period m times the horizontal scanning period, picture element data stored in said first line memory is read out and written in said first field memory, and picture element data stored in said first and second field memories are supplied to said output circuit alternately at intervals of one horizontal scanning period.

4. A solid state imaging apparatus according to claim 1 further comprising a luminance detection circuit and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit for outputting accumulation data and supplying the data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance of an object.

7. A solid state imaging apparatus according to claim 1 further comprising a luminance detection circuit, a motion detection circuit for detecting motion of an object, and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit and an output signal of said motion detection circuit for supplying accumulation data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance and motion of the object.

2. A solid state imaging apparatus having photoelectric conversion means comprised of an array of plural photoelectric conversion devices disposed in two dimensions for converting optical information into analog electrical picture element data and means for digitizing the picture element data obtained by said array of photoelectric conversion devices and sequentially reading out the digitized picture element data;

and an output circuit to which the picture element data is input and from which a picture signal is output;

said solid state imaging apparatus comprising;

two memories each thereof having a capacity at least for storing the picture element data for one field;

first switching means for connecting said two memories alternately to said output circuit;

first signal generator means for generating a control signal for setting the accumulation period on said array of photoelectric conversion devices to m (m>

1) times the field period and a write address for said memory;

second signal generator means for generating a read address for reading out digitized picture element data from said memory at intervals of one field period; and

second switching means for supplying the write address generated by said first signal generator means and the read address generated by said second signal generator means to said two memories such that the write address is supplied to one memory and the read address is supplied to the other memory, alternately;

wherein

digitized picture element data obtained from said photoelectric conversion means is written in one memory of said two memories during a period m times the field period, and during that period, digitized picture element data is read out from the other memory m times at intervals of one field period and the thus read out picture element data is supplied to said output circuit,

further comprising a luminance detection circuit and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit for outputting accumulation data and supplying the data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance of an object.

5. A solid state imaging apparatus according to claim 2 further comprising a luminance detection circuit, a motion detection circuit for detecting motion of an object, and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit and an output signal of said motion detection circuit for supplying accumulation data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance and motion of the object.

3. A solid state imaging apparatus having photoelectric conversion means comprised of an array of plural photoelectric conversion devices disposed in two dimensions for converting optical information into analog electrical picture element data and means for digitizing the picture element data obtained by said array of photoelectric conversion devices and sequentially reading out the digitized picture element data;

and an output circuit to which the picture element data is input and from which a picture signal is output;

said solid state imaging apparatus comprising;

two frame memories each thereof having a capacity for storing the picture element data for one frame;

first switching means for connecting said one frame memory of said two frame memories to said photoelectric conversion means and the other frame memory to said output circuit, alternately;

first signal generator means for generating a control signal for setting the accumulation period on said array of photoelectric conversion devices to m (m>

1) times the field period and supplying this signal to said photoelectric conversion means and also generating a write address for said frame memory;

second signal generator means for generating a read address for reading out digitized picture element data from said frame memory at intervals of one field period; and

second switching means for supplying the write address generated by said first signal generator means and the read address generated by said second signal generator means to said two frame memories such that the write address is supplied to one memory and the read address is supplied to the other frame memory, alternately for each frame;

wherein

said photoelectric conversion means outputs digitized picture element data during a period m times the field period according to the control signal supplied from said first signal generator means, the digitized picture element data output from said photoelectric conversion means is written in one memory of said two frame memories during a period m times the field period, and during that period, picture element data is read out from the other memory m times at intervals of one field period and the thus read out picture element data is supplied to said output circuit,

further comprising a luminance detection circuit and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit for outputting accumulation data and supplying the data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance of an object.

6. A solid state imaging apparatus according to claim 3 further comprising a luminance detection circuit, a motion detection circuit for detecting motion of an object, and an accumulation period controlling circuit in response to an output signal of said luminance detection circuit and an output signal of said motion detection circuit for supplying accumulation data to said first signal generator means, whereby the accumulation period on said array of photoelectric conversion devices is controlled according to luminance and motion of the object.