IR Camera

• US 20060219920A1
• Filed: 04/05/2005
• Published: 10/05/2006
• Est. Priority Date: 04/05/2005
• Status: Abandoned Application

• Current Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Original Assignee: Flir Systems AB (Teledyne Technologies Incorporated)
• Inventors: Wijk, Jonas, Koylouglu, Ayse
• Application Number:
  US10/907,529
• Publication Number:
  US 20060219920A1
• Time in Patent Office: Days
• US Class Current: 250/332
• CPC Class Codes: G01J 1/18 using comparison with a reference electric value
• CPC Class Codes: G01J 2005/0077 Imaging
• CPC Class Codes: G01J 5/02 Constructional details
• CPC Class Codes: G01J 5/026 Control of working procedures of a pyrometer, other than calibration; Bandwidth calculation; Gain control
• CPC Class Codes: G01J 5/80 Calibration using comparison with reference sources G01J5/52
• CPC Class Codes: H04N 23/23 from thermal infrared radiation
• CPC Class Codes: H04N 25/68 applied to defects
• 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

An IR camera (1) for use within a predetermined scene temperature range comprises a focal plane array (7), and a signal processing device (9) arranged to receive an incoming signal from pixels of the focal plane array (7). The signal processing device (9) is arranged, for each image, to perform the following steps; identify any pixels of the focal plane array (7) for which the incoming signal, anywhere inside the scene temperature range, is equal to or larger than the predetermined maximum value, or equal to or less than the predetermined minimum value, replace the value of each element thus identified with a replacement value based on the value of at least one neighbouring element. By performing this in real time instead of permanently disabling any element that reaches the maximum or minimum value within the scene temperature range of the camera, the quality of the image is improved.

Claims

1. An IR camera (1) comprising a focal plane array (7), said focal plane array (7) comprising an array of elements for registering incoming IR radiation from an object, and a signal processing device (9) arranged to receive an incoming signal from each element indicative of the incoming IR radiation in said elements, said incoming signal having a predetermined minimum value and a predetermined maximum value, and to process said incoming signal from each of the elements to obtain a temperature value in order to generate a thermal image of the object, said camera (1) having a predetermined scene temperature range and being characterized in that said signal processing device (9) is arranged, for each image, to perform the following steps

identify any elements of the focal plane array (7) for which the incoming signal, anywhere inside the scene temperature range, is equal to or larger than the predetermined maximum value, or equal to or less than the predetermined minimum value,

replace the value of each element thus identified with a replacement value based on the value of at least one neighbouring element.

2. An IR camera according to claim 1, wherein the elements of the focal plane array (7) are arranged to convert the incoming IR radiation to a voltage signal and further comprising means for converting the voltage signal to a digital signal representing the incoming signal.

3. An IR camera according to claim 1 or 2, wherein the signal processing device (9) is arranged to determine the replacement value for a particular identified element as the value of a neighbouring element of the identified element.

4. An IR camera according to claim 1 or 2, wherein the signal processing device (9) is arranged to determine the replacement value for a particular identified element on the basis of at least two neighbouring elements of the element.

5. A method for use with an IR camera having a predetermined scene temperature range and having a focal plane array comprising a plurality of pixels, for registering incoming IR radiation from an object, said method comprising the steps of

converting incoming IR radiation in each pixel to a level signal having a predefined minimum value and a predefined maximum value,

using said level signal from each of the plurality of pixels to obtain a temperature value in order to generate a thermal image, said method being characterized in that it comprises the steps of:

identifying pixels whose incoming signal, anywhere inside the scene temperature range, is equal to or larger than the predetermined maximum value, or equal to or less than the predetermined minimum value

for the pixels thus identified, replacing the value of each element thus identified with a replacement value based on the value of at least one neighbouring element.

6. A method according to claim 5, comprising the steps of converting the incoming IR radiation in each element to a voltage signal and converting the voltage signal to a digital signal representing the level of incoming IR radiation.

7. A method according to claim 5 or 6, wherein the replacement value for a particular identified element is determined as the value of a neighbouring element of the identified element.

8. A method according to claim 5 or 6, wherein the replacement value for a particular identified element is determined on the basis of at least two neighbouring elements of the element.