Cameras

• US 6,633,333 B1
• Filed: 10/01/1997
• Issued: 10/14/2003
• Est. Priority Date: 10/02/1996
• Status: Expired due to Term

• Current Assignee: E2V Technologies PLC
• Original Assignee: GEC Marconi Limited (Gooding Consumer Electronics Ltd.)
• Inventors: Spencer, Simon Howard
• Primary Examiner(s): MOE, AUNG SOE
• Application Number:
  US08/942,538
• Time in Patent Office: 2,204 Days
• Field of Search: 348/272, 348/271, 348/273, 348/274, 348/275, 348/276, 348/277, 348/280, 348/241, 348/242, 348/252, 348/253, 348/217, 348/222, 348/223, 348/225, 348/270, 348/256, 348/292, 348/342, 348/263, 348/630, 348/631, 348/624, 348/713, 348/222.1, 348/217.1, 348/223.1, 348/225.1, 382/162, 382/167, 358/512, 358/513, 358/515, 358/517
• US Class Current: 348/272
• CPC Class Codes: H04N 23/84 for processing colour signals
• CPC Class Codes: H04N 25/131 including elements passing infrared wavelengths
• CPC Class Codes: H04N 25/133 including elements passing panchromatic light, e.g. filters passing white light
• CPC Class Codes: H04N 25/135 based on four or more different wavelength filter elements

Abstract

A camera producing colour video outputs may employ an image intensifier 5 and a monochrome CCD sensor 3. The scene is exposed through filters F₃, F₄ which may each contain stripes of subtractive primary colours alternating with clear regions. The video is decoded using waveforms derived from a memory which records the output of the sensor when imaged on, for example, primary colours such as red and blue, producing trains of pulses which identify the spatial regions of each line corresponding to the spatial areas of the pattern on the sensor produced by the colour filters F₃, F₄, in order that actual scenes can be decoded using the stored waveforms, for example using sample and hold devices. A colour interference signal is generated in matrix addition circuitry 10 to produce a luminance signal which has stripe visibility removed from it, permitting high resolution video signals to be obtained.

Claims

1. A camera comprising a sensor, said sensor comprising a series of pixels for receiving radiation forming an image of a scene, filter means positioned in the path of radiation incident on the sensor, said filter means being arranged to pass different spectral regions in different spatial regions, so that different spatial regions of the sensor are exposed to radiation of different spectral regions, decoding means for producing separate outputs from the sensor corresponding to the different spectral regions, memory means for storing sensor output signals and a circuit for using the outputs corresponding to the different spectral regions to remove visibility of the different spectral regions from the sensor output, to permit high resolution to be attained, in which said decoding means is further arranged to use stored signals derived from the sensor output corresponding to exposure of the sensor through the filter means by radiation of referenced spectral regions, said stored signals being representative of the position of the reference spectral regions with respect to the position of said pixels.

2. A camera as claimed in claim 1, the decoding means further including a waveform generator for generating pulses derived from the stored signals which are applied to sample and hold means which receive a signal derived from the sensor output.

3. A camera as claimed in claim 1, in which the stored signals are square waves derived from the sensor output.

4. A camera as claimed in claim 1, in which the sensor is arranged to produce an output representative of lines of the image, and the filter means comprises stripes orientated obliquely to the lines of the image.

5. A camera as claimed in claim 4, in which the stripes are formed of two sets, one set comprising stripes passing one spectral region alternating with stripes passing all spectral regions of the sensor, and the second set comprising stripes passing another spectral region alternating with stripes passing all spectral regions of the sensor.

6. A camera as claimed in claim 5, in which the said one spectral region and the said other spectral region are subtractive primary colours, and the alternating stripes are clear.

7. A camera as claimed in claim 6, in which the subtractive primary colours are yellow and cyan.

8. A camera as claimed in claim 5, in which the pitch of the stripes and the alternating regions are equal, and each set of stripes is inclined at an angle to the line direction.

9. A camera as claimed in claim 5, in which the sets of stripes are inclined to different sides of a notional vertical line of the image.

10. A camera as claimed in claim 1, in which the reference spectral regions are primary colours.

11. A camera as claimed in claim 5, in which the filter means lies at the image plane of the sensor or at the focus of a relay lens for the sensor.

12. A camera as claimed in claim 1, in which the sensor includes an image intensifier.

13. A camera as claimed in claim 12, in which the sensor includes a solid state imager.

14. A camera as claimed in claim 1, in which the sensor is an infra-red sensor.