Single sensor video imaging system and method using sequential color object illumination

• US 5,264,925 A
• Filed: 06/26/1992
• Issued: 11/23/1993
• Est. Priority Date: 06/26/1992
• Status: Expired due to Term

• Current Assignee: Surgicon, Inc.
• Original Assignee: Life Surgery, Inc.
• Inventors: Shipp, John I., Goodell, John L.
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US07/905,278
• Time in Patent Office: 515 Days
• Field of Search: 358/41, 358/43, 358/44, 358/909, 358/75
• US Class Current: 348/269
• CPC Class Codes: H04N 13/194 Transmission of image signals
• CPC Class Codes: H04N 13/211 using temporal multiplexing
• CPC Class Codes: H04N 13/218 using spatial multiplexing
• CPC Class Codes: H04N 13/239 using two 2D image sensors having a relative position equal to or related to the interocular distance H04N13/243 takes precedence
• CPC Class Codes: H04N 13/254 in combination with electromagnetic radiation sources for illuminating objects
• CPC Class Codes: H04N 13/257 Colour aspects
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 13/341 using temporal multiplexing
• CPC Class Codes: H04N 13/398 Synchronisation thereof; Control thereof
• CPC Class Codes: H04N 23/125 Colour sequential image capture, e.g. using a colour wheel

Abstract

A color video processing method in which three primary color signals are obtained sequentially from a single monochrome photo sensor array. RGB signals are obtained by twice delaying the output of the sensor by non-color specific delays equal to a standard field period, and matrix switching the sequential RGB signals to their respective outputs.

Claims

1. A method of processing color video images in a single sensor camera system using sequential illumination of an object by first, second and third primary color light sources, said method comprising the steps of:

a. illuminating said object with light from said first primary color light source during a first illumination period equal to a standard television field period;

b. illuminating said object with light from said secondary primary color light source during a second illumination period equal to a standard television field period;

c. illuminating said object with light from said third primary color light source during a third illumination period equal to a standard television field period;

d. illuminating said object with light from said first primary color light source during a fourth illumination period equal to a standard television field period;

e. focusing onto said sensor light reflected by said object during said first and during repeating sequences of said second, third, and fourth illumination periods;

f. during said second illumination period, capturing from said sensor an analog signal corresponding to the level of a first primary color light focused on said sensor during said first illumination period, thereby providing a first primary color captured signal;

g. digitizing said first primary color captured signal, thereby providing a digitized first primary color captured signal;

h. switching said digitized first primary color captured signal to the input of a first primary color digital-to-analog converter and converting said digitized first primary color captured signal back to analog form, thereby providing an odd field reconverted first primary color signal;

i. using said odd field reconverted first primary color signal to represent an odd field television video signal of a first primary color;

j. during said third illumination period, capturing from said sensor an analog signal corresponding to the level of a second primary color light focused on said sensor during said second illumination period, thereby providing a second primary color captured signal;

k. digitizing said second primary color captured signal, thereby providing a digitized second primary color captured signal;

l. switching said digitized second primary color captured signal to the input of a second primary color digital-to-analog converter and converting said digitized second primary color captured signal back to analog from, thereby providing an even field reconverted second primary color signal;

m. using said even field reconverted second primary color signal to represent an even field television video signal of a second primary color;

n. during said third illumination period, delaying in a first delay unit said digitized first primary color captured signal by a time equal to said standard television field period, thereby providing a delayed digitized first primary color signal, and directing said delayed digitized first primary color signal to said first primary digital-to-analog converter, and reconverting said delayed digitized first primary color signal back to analog form, thereby providing an even field reconverted first primary color signal;

o. using said even field reconverted first primary color signal to represent an even field television video signal of said first primary color;

p. during said fourth illumination period, capturing from said sensor an analog video signal corresponding to the level of a third primary color light focused on said sensor during said third illumination period, thereby providing a third primary color captured signal;

q. digitizing said third primary color captured signal, thereby providing a digitized third primary color captured signal;

r. switching said digitized third primary color captured signal to the input of a third primary color digital-to-analog converter and converting said digitized third primary color captured signal back to analog form, thereby providing an odd field reconverted third primary color signal;

s. using said odd field reconverted third primary color signal to represent an odd field television video signal of a third primary color;

t. during said fourth illumination period, delaying in a second delay unit said delayed digitized first primary color signal by a time equal to said standard television field period, thereby providing a further delayed digitized first primary color signal, directing said further delayed digitized first primary color signal to said first primary color digital-to-analog converter, and reconverting said further delayed digitized first primary color signal back to analog form, thereby providing another odd field reconverted first primary color signal;

u. using said other odd field reconverted first primary color signal to represent an odd field television video signal of said first primary color;

v. during said fourth illumination period, delaying in said first delay unit said digitized second primary color captured signal by a time equal to said standard television field period, thereby providing a delayed digitized second primary color signal, directing said delayed digitized second primary color signal to said second primary color digital-to-analog converter, and re-converting said delayed digitized second primary color signal back to analog form, thereby providing an odd field reconverted second primary color signal; and

w. using said odd field reconverted second primary color signal to represent an odd field television video signal of said second primary color.

2. The method of claim 1 further comprising the step of transmitting said odd and even field television video signals of said first, second, and third primary colors to a color video monitor.

3. The method of claim 1 further comprising the steps of transmitting said odd and even field television video signals of said first, second, and third primary colors to the inputs of a television signal modulator, and transmitting corresponding composite luminance and chrominance signals from said modulator for display on a television receiver means.

4. The method of either of claims 1, 2, or 3, further comprising the steps of:

a. adding to each of said first, second, and third primary color captured signals a color identification signal that identifies which of said first, second, or third primary colors corresponds to said each of said first, second, and third primary color captured signals thereby providing first, second, and third combined primary color and color identification signals;

b. transmitting said first, second, and third combined primary color and color identification signals to a remote receiver for further processing.

5. A video imaging system comprising:

a. means for sequentially illuminating an object, said illuminating means including at least first, second, and third primary color light sources and means for separately and successively activating said light sources for equal standard television field periods;

b. means for focusing a primary color light reflected from said object onto a sensor, said sensor providing a primary color level analog data responsive to the level of said primary color light focused onto said sensor;

c. means for capturing said primary color level analog data from said sensor;

d. A/D converter means for converting said captured primary color level analog data to digital format, thereby providing digitized captured primary color level data;

e. first delay means coupled to the output of said A/D converter means for delaying for a standard television field period said digitized captured primary color level data;

f. second delay means coupled to the output of said first delay means for further delaying for a standard television field period said digitized captured primary color level data;

g. first, second, and third digital-to-analog converter means for converting said digitized captured primary color level data from said A/D converter means, from said first delay means, and from said second delay means, thereby providing re-converted first, second and third primary color level analog data, said re-converted first, second and third primary color level analog data representing color television video signals corresponding to first, second, and third primary colors; and

h. means for successively switching the outputs of said A/D converter means, said first delay means, and said second delay means to said first, second, and third digital-to-analog converter means.

6. The apparatus of claim 5 further comprising television monitor means operatively connected to the outputs of said first, second, and third digital-to-analog converter means.

7. The apparatus of claim 5, further comprising means for wireless transmission of said primary color level analog data from said sensor to a remote location.