Electronic still camera

• US 4,131,919 A
• Filed: 05/20/1977
• Issued: 12/26/1978
• Est. Priority Date: 05/20/1977
• Status: Expired due to Term

• Current Assignee: Eastman Kodak Company
• Original Assignee: Eastman Kodak Company
• Inventors: Sasson, Steven J., Lloyd, Gareth A.
• Primary Examiner(s): Konick, Bernard
• Assistant Examiner(s): Faber, Alan
• Application Number:
  US05/798,956
• Time in Patent Office: 585 Days
• Field of Search: 360/9, 360/10, 360/8, 360/35, 360/33, 179/2 TV, 358/127, 358/134, 358/213, 358/85, 358/133, 358/78
• US Class Current: 386/225
• CPC Class Codes: H04N 1/00129 with a display device, e.g. CRT or LCD monitor with a television apparatus H04N1/00283; arrangements for control of display devices G09G
• CPC Class Codes: H04N 1/2112 using still video cameras
• CPC Class Codes: H04N 1/2137 with temporary storage before final recording, e.g. in a frame buffer
• CPC Class Codes: H04N 1/2158 using a detachable storage unit
• CPC Class Codes: H04N 2101/00 Still video cameras
• CPC Class Codes: H04N 7/122 involving expansion and subsequent compression of a signal segment, e.g. a frame, a line
• CPC Class Codes: Y10S 358/906 Hand-held camera with recorder in a single unit

Abstract

Electronic imaging apparatus, preferably an electronic still camera, employs an inexpensive information-recording medium such as audio-grade magnetic tape for "capturing" scene images. The camera includes a charge coupled device comprised of an array of photosensitive elements which form a charge pattern corresponding to an optical image projected onto the elements during an exposure interval. A charge transfer circuit converts the charge pattern into a high frequency pulsed electrical signal immediately following the exposure interval to remove the charge from the device in a short period of time to maintain unwanted "dark current" at a low level. Each pulse represents the image-forming light projected onto a particular photosensitive element. A high speed analog-to-digital converter converts these pulses to multi-bit digital words in real time. A digital buffer memory temporarily stores these words, then retransmits them at a rate that is compatible for recording on the audio-grade tape. The image can be displayed on a conventional television receiver by reading the recorded words from the tape and converting them to a format compatible with the signal-receiving circuitry of the television.

Claims

1. In an electronic still camera having a solidstate light-responsive device for producing at a relatively high rate a stream of discrete signals indicative of optical images received by said device during adjacent exposure intervals, the improvement comprising:

(a) means for extracting said discrete signals from said light-responsive device during a time interval which is no greater than the interval during which said optical images are produced;

(b) circuit means for separating said signals from each other;

(c) means for transforming said separated signals into a stream of signals occurring at a rate which is slower than said high rate; and

(d) means for recording in real time on a non-volatile medium said slower rate stream of signals.

2. Apparatus as set forth in claim 1 wherein said transforming means comprises storage means for enabling production of said high rate stream of signals and recording of said slower rate stream of signals to occur concurrently.

3. In an electronic still camera having a solid-state light-responsive device located to receive an optical image, said light-responsive device including electrical addressing means for producing families of electrical signals relating to charge patterns formed in said light-responsive device during successive exposure intervals, each signal within a family corresponding to a charge pattern formed during one exposure interval and each of said signals defining a first train of information bearing indices occurring at a first relatively high rate, the improvement comprising:

(a) control means for providing a signal to said electrical addressing means to extract said families of electrical signals from said lightresponsive device at a speed which is at least as great as the speed at which said charge patterns are formed;

(b) electrical gating means for effectively isolating at one of said electrical signals from the other of said electrical signals;

(c) means associated with said gating means for transforming the electrical signal which has been isolated into a second train of information bearing indices occurring at a rate which is substantially less than said first rate of said first train of information bearing indices; and

(d) means for recording on a medium said second train of information bearing indices.

4. In an electronic still camera having a solid-state imaging device located at an exposure plane, means associated with said imaging device for forming charge patterns relating to optical images projected onto said imaging device during adjacent exposure intervals, the improvement comprising:

(a) means for producing a stream of discrete electrical signals, representative of said charge patterns, at a speed which is at least as great as the speed at which said charge patterns are formed;

(b) electrically energizable circuit means for separating a one of said electrical signals from the other of said electrical signals;

(c) means responsive to said separated electrical signal for producing a plurality of multi-bit words indicative of said separated electrical signal, said digital words being produced in real time;

(d) data storage means;

(e) means for transferring said digital words into said data storage means in real time at a first relatively high rate;

(f) means for retrieving said digital words from said data storage means at a second rate that is substantially lower than said first relatively high rate; and

(g) recording apparatus for recording said retrieved digital words on a non-volatile recording medium, said recording apparatus having a recording speed that is compatible with said second rate.

5. In an electronic still camera having a light-responsive device located at an exposure plane for producing charge patterns relating to optical images projected onto said light-responsive device during adjacent exposure intervals, the improvement comprising:

(a) control means for providing a signal;

(b) electrical addressing means associated with said light-responsive device and responsive to said signal for extracting from said light-responsive device information-bearing electrical signals corresponding to said charge patterns at a speed which is at least as great as the speed at which said charge patterns are formed;

(c) electronic shutter control means having (1) a first state for blocking transmittal of said electrical signals, and (2) a second state for transmitting a one of said electrical signals;

(d) actuatable means for switching said control means from its state into its second state;

(e) a signal storage device for receiving and storing in real time at a first data rate representations corresponding to said transmitted electrical signal;

(f) means for retrieving said representations from said signal storage device at a second data rate that is substantially less than said first rate; and

(g) recording apparatus for recording said representations on a non-volatile recording medium, said recording apparatus having a recording speed that is suitable for recording said representations at the rate at which said representations are retrieved from said signal storage device.

6. An electronic still camera as set forth in claim 5 including means for automatically switching said control means from said second state back to said first state following transmittal of said information-bearing electrical signal.

7. In an electronic still camera having a solid-state light-responsive imaging device located to receive optical images, the improvement comprising:

(a) electrical addressing means associated with said imaging device for producing families of electrical signals derived from optical images formed on said imaging device during adjacent exposure intervals, each signal within a family corresponding to an optical image formed during one exposure interval and said signals being produced at a first rate which is at least as great as the rate at which said optical images are formed;

(b) electrical gating means having (1) a first state for blocking transmittal of said electrical signals, and (2) a second state for transmitting said electrical signals;

(c) switching means synchronized with said electrical addressing means for switching said electrical gating means from said first state into said second state then back to said first state for transmitting a given one of said electrical signals;

(d) means for temporarily storing representations of said transmitted electrical signal in real time and for retransmitting said representations at a second rate that is substantially less than said first rate; and

(e) recording apparatus for recording said representations on a non-volatile recording medium, said recording apparatus having a signal access speed that is compatible with the second rate at which said representations are retransmitted.

8. In an electronic still camera including a charge coupled device defining an array of light-sensitive elements located at an exposure plane, the improvement comprising:

(a) electrical addressing means associated with said light-sensitive elements for producing families of pulsed electrical signals relating to optical images projected onto said elements during contiguous exposure intervals, said signals being produced at a rate which is at least as great as the rate at which said optical images are formed;

(b) an electrical gating means having (1) a first state for blocking transmittal of said pulsed electrical signals, and (2) a second state for transmitting said electrical signals;

(c) actuatable switching means for switching said gating means from said first state into said second state;

(d) said electrical gating means including means for automatically switching said gating means from said second state back to said first state following transmittal of the first one of said electrical signals which occurs after actuation of said switching means;

(e) a digital data storage device;

(f) converter means for converting in real time said pulses in said first one of said electrical signals into a multi-bit digital word;

(g) means for transferring said digital words in real time into said digital data storage device;

(h) means for retrieving said digital words from said data storage device at a rate that is more than an order of magnitude less than the rate at which said words are transferred into said storage device; and

(i) recording apparatus coupled to said digital words retrieving means for recording said digital words on a magnetic recording medium, said recording apparatus having a recording speed that is compatible with recording signals at an audio-grade recording rate.