Method and apparatus for producing a false color image

• US 5,557,326 A
• Filed: 07/18/1994
• Issued: 09/17/1996
• Est. Priority Date: 11/27/1991
• Status: Expired due to Fees

• Current Assignee: Valtion Teknillinen Tutkimuskeskus
• Original Assignee: Valtion Teknillinen Tutkimuskeskus
• Inventors: Hame, Tuomas, Rantasuo, Markku
• Primary Examiner(s): Metjahic, Safet
• Assistant Examiner(s): HSIA, SHERRIE Y
• Application Number:
  US08/244,433
• Time in Patent Office: 792 Days
• Field of Search: 348/272, 348/273, 348/280, 348/164, 348/166, 348/29, 348/33, 348/34
• US Class Current: 348/272
• CPC Class Codes: H04N 23/11 for generating image signals from visible and infrared light wavelengths
• CPC Class Codes: H04N 23/84 for processing colour signals
• CPC Class Codes: H04N 5/33 Transforming infrared radiation cameras or camera modules for generating image signals from infrared radiation H04N23/20; circuitry of SSIS for transforming infrared radiation into image signals H04N25/20

Abstract

A method for creating a false color image, by utilizing a video camera provided with two or three arrays of semiconductor detectors, the sensitivity range whereof, in relation to wavelength, extends from the visible light range to near infrared radiation range, and where the radiation received in the semiconductor detectors is filtered. The radiation received in the first array of semiconductor detectors is filtered so that only near infrared radiation is given access to the detector array. Further, the radiation received in the second semiconductor detector array, or alternatively in the second and third semiconductor detector arrays is filtered so that of the radiation of the visible spectrum range, green and red are given access to the detector array or arrays. The signals obtained from the first and second semiconductor detector arrays, or alternatively from the first, second and third semiconductor detector arrays, representing the strength of near infrared radiation and the strength of the radiation of the green and red spectrum ranges, are decoded by changing the order of the signals in order to achieve a desired false color signal in the camera output.

Claims

1. A method for producing a false color image, using a video camera provided with first and second arrays of semiconductor detectors, the first and second arrays having a sensitivity range in relation to wavelength extending from visible light to near infrared radiation;

and where radiation received in the first and second arrays is filtered, the method comprising;

filtering the radiation received in the first array to provide that only the near infrared radiation (ir) is given access to the first array;

filtering the radiation received in the second array to provide that only the radiation of green (g) and red (r) spectrum ranges are given access to the second array; and

decoding signals (ir, g r) received from the first and second arrays representing strength of the near infrared radiation (ir) and strength of the radiation of the green (g) and red (r) spectrum ranges, by changing order of the signals to achieve a desired combined false color signal (g r, ir) in a camera output.

2. A method for producing a false color image, utilizing a video camera provided with first, second, and third arrays of semiconductor detectors, the first, second, and third arrays having a sensitivity range in relation to wavelength extending from visible light to near infrared radiation;

and where radiation received in the first, second, and third arrays is filtered, the method including the steps of;

filtering the radiation received in the first array to provide that only the near infrared radiation (ir) is given access to the first array;

filtering the radiation received in the second array to provide that only the radiation of green (g) spectrum range is given access to the second array;

filtering the radiation received in the third array to provide that only the radiation of red (r) spectrum range is given access to the third array;

decoding signals (ir, g, r) received from the first, second and third arrays representing strength of the near infrared radiation (ir) and strength of the radiation of the green (g) and red (r) spectrum ranges, by changing order of the signals to achieve a desired combined false color signal (g, r, ir) in a camera output.

3. The method of claim 2 for producing a false color image, wherein the decoding step includes rearranging the signals representing the strength of the near infrared radiation and the radiation from the green (g) and red (r) spectrum ranges into an order green (g), red (r) and infrared (ir) in the camera output.

4. The method of claim 2 for producing a false color image, wherein the decoding step includes rearranging the signals representing the strength of radiation of the green (g) spectrum range and the near infrared radiation (ir) in reversed order into green (g) and near infrared (ir), whereas the signal representing the radiation of the red (r) spectrum range is maintained in the camera output.

5. An apparatus for producing a false color image, comprising:

a video camera provided with first and second arrays of semiconductor detectors and a first color separation filter system, the first and second arrays having a sensitivity range in relation to wavelength extending from visible light to near infrared radiation;

a decoder; and

a second filter system including,

a first filter for attenuating wavelengths of blue light (b), the first filter being arranged in cooperation with the first array of semiconductor detectors to provide that received radiation is filtered so that only the near infrared radiation (ir) is given access to the first array;

a second filter for attenuating the near infrared radiation (ir), the second filter being arranged in cooperation with the second array of semiconductor detectors to provide that received radiation is filtered so that only the radiation of red (r) and green (g) spectrum ranges are given access to the second array; and

that signals (ir, g r) obtained from the first and second arrays and representing strength of the near infrared radiation (ir) and strength of the radiation of the green (g) and red (r) spectrum ranges, are decoded in the decoder by changing an order of the signals to achieve a desired combined false color signal (g r, ir) in an output of the camera.

6. An apparatus for creating a false color image, comprising:

a video camera and a first color separation filter system, the video camera including first, second, and third arrays of semiconductor detectors;

a decoder; and

a second filter system including,

a first filter attenuating wavelengths of blue light (b), the first filter being arranged to cooperate with the first array to provide that received radiation is filtered so that only near infrared radiation (ir) is given access to the first array;

a second filter attenuating the near infrared radiation (ir), the second filter being arranged to cooperate with the second array to provide that received radiation is filtered so that only the radiation of green (g) spectrum range is given access to the second array;

a third filter (17) attenuating the near infrared radiation (ir), the third filter being arranged to cooperate with the third array to provide that received radiation is filtered so that only the radiation of red (r) spectrum range is given access to the third array;

wherein signals (ir, g, r) obtained from the first, second and third arrays and representing strength of the near infrared radiation (ir) and strength of the green (g) and red (r) radiation, are decoded in the decoder by changing an order of the signals to achieve a desired combined false color signal (g, r, ir;

g, ir, r) in an output of the camera.