Infrared scanning apparatus using a plurality of parallel detectors

Claim 2

In a noncontacting apparatus for detecting a characteristic of an article: means for transferring heat to an incremental area of a surface of the article to heat the area; at least two heat detector means, each for detecting the thermal radiation response in the same range of radiation wavelengths of a separate one of at least two discrete incremental areas of the surface externally of the heated area, and for generating a signal in accordance therewith; means for scanning the heat transfer means and the heat detector means in unison with each other and over the surface of the article to generate signals from the heat detector means which vary in accordance with the thermal radiation responses, in the same range of radiation wavelengths, of the scanned incremental areas, and output indicator means for receiving the signals from the heat detector means.

Claim 3

In the noncontacting apparatus as set forth in claim 1, wherein: the means for transferring heat to an incremental area of the surface to heat the area includes means for directing a beam of infrared radiation onto the area, and the heat detector means includes individual pickup means which are each responsive to the detected infrared radiation, in the same range of radiation wavelengths, from a separate one of the incremental areas for generating a signal in accordance therewith, the signal being a function of the heat transfer characteristic of the article at the detected incremental area.

Claim 4

In the noncontacting apparatus as set forth in claim 2, wherein the means for scanning the heat transfer means and the heat detector means over the surface of the article includes optical scan means, coupled with both the beam of infrared radiation and the pickup means, for scanning the beam of infrared radiation and the pickup means across the surface of the article in a predetermined pattern and in unison with each other.

Claim 5

In the noncontacting apparatus as set forth in claim 3, wherein the output means for receiving the signals from the heat detector means includes: aMplifier means, for receiving the signals from the pickup means, and for generating output signals in accordance therewith, and visual indicator means, for receiving the signals from the amplifier means for generating a separate visual indication of the heat transfer characteristics of the incremental areas being scanned by each individual pickup means, and for generating a composite visual indication, from each of the separate visual indications, of the heat transfer characteristics of all of the incremental areas being scanned by all of the pickup means.

Claim 6

In a scanning apparatus for detecting a thermal response characteristic of a workpiece: means for focusing a beam of radiation onto an incremental area of a surface of the workpiece to heat the area; at least two radiation sensing devices, each for receiving radiation and for generating an electrical signal in accordance with the intensity of the received radiation which is in a predetermined range of radiation wavelengths; means for focusing each radiation sensing device along an optical path and onto a separate and discrete incremental area of the surface of the workpiece in close, nonoverlapping proximity with the heated area, to generate an electrical signal from each sensing device in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the incremental area onto which the sensing device is focused; means for scanning the beam of radiation and the optical paths of the radiation sensing devices across the surface of the workpiece, with the heated incremental area and the sensed incremental areas maintained in a fixed spatial orientation with respect to each other and with not more than one of the radiation sensing devices sensing incremental areas of the surface which are scanned by the beam of radiation, to generate signals from the sensing devices which vary in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the scanned incremental areas, and means for indicating the value of the electrical signals generated by the sensing devices as the optical paths of the sensing devices are scanned across the surface of the workpiece.

Claim 7

In a scanning apparatus for detecting a thermal response characteristic of a workpiece: means for focusing a beam of radiation onto an incremental area of a surface of the workpiece to heat the area; at least two radiation sensing devices, each for receiving radiation and for generating an electrical signal in accordance with the intensity of the received radiation which is in a predetermined range of radiation wavelengths; means for focusing each radiation sensing device along an optical path and onto a separate and discrete incremental area of the surface of the workpiece in close, nonoverlapping proximity with the heated area, to generate an electrical signal from each sensing device in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the incremental area onto which the sensing device is focused; means for scanning the beam of radiation and the optical paths of the radiation sensing devices across the surface of the workpiece, with the heated incremental area and the sensed incremental areas maintained in a fixed spatial orientation with respect to each other and with not more than one of the radiation sensing devices sensing incremental areas of the surface which are scanned by the beam of radiation, to generate signals from the sensing devices which vary in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the scanned incremental areas, and means for indicating the value of the electrical signals generated by the sensing devices as the optical paths of the sensing devices are scanned across the surface of the workpiece.

Claim 8

In a scanning apparatus as in claim 5, wherein: each radiation sensing device is a radiometer, and the scanning means includes a. a first plane mirror, adapted for oscillating movement in a first direction, and positioned both in the path of the beam of radiation, and in the optical paths of the radiometers, to scan the beam of radiation and the optical paths of the radiometers across the surface of the article in the first direction, b. means for oscillating the first plane mirror in the first direction, c. a second plane mirror, adapted for oscillating movement in a second direction, and positioned both in the path of the beam of radiation, and in the optical paths of the radiometers, to scan the beam of radiation and the optical paths of the radiometers across the surface of the article in the second direction, and d. means for oscillating the second plane mirror in the second direction, and the means for indicating the value of the electrical signals generated by the radiometers includes a. a multi-gun cathode ray tube, each gun of which receives an input, which varies in accordance with the electrical signal from a separate one of the radiometers, and generates on the screen of the tube a separate raster image which correspondingly varies in accordance with the electrical signal; b. first sweep means, synchronously coupled with the means for oscillating the first plane mirror in the first direction, for sweeping the rasters, generated by the guns, across the screen of the tube in a direction which corresponds with the first direction, and c. second sweep means, synchronously coupled with the means for oscillating the second plane mirror in the second direction, for sweeping the rasters, generated by the guns, acrOss the screen of the tube in a direction which corresponds with the second direction, to generate a composite image on the screen of the tube, with each of the individual raster images, which is a representation of the thermal response experienced by the surface of the workpiece as it is scanned by the beam of radiation.

Claim 9

In a scanning apparatus as in claim 6, wherein the first and second directions are orthogonal with respect to each other.

Claim 10

In a nondestructive apparatus for detecting a thermal characteristic of an article: means for focusing radiation from a source of radiation into a beam for projection onto an incremental area of a surface of the article to heat the area and, by the thermal conduction of the article, to heat the surrounding area; at least three radiation pickup devices, each for sensing the intensity of radiation in a predetermined range of radiation wavelengths and for generating an electrical signal which varies in accordance with the intensity thereof; means for focusing an image of a separate and discrete incremental area of the surface of the article adjacent to the heated area along an optical path and onto each pickup device for detection thereby to generate an electrical signal with each pickup device in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by its detected incremental area; means for intermittently interrupting both the beam of radiation and the optical path to the pickup devices to pulse both the beam of radiation on the surface and the radiation detected by the pickup devices; a first optical deflection device, both in the path of the beam of radiation and in the optical paths of the pickup devices, for repetitively sweeping both the beam of radiation and the image focused on each pickup device across the surface of the article in a first direction and in a fixed orientation with each other; a second optical deflection device both in the path of the beam of radiation and the optical paths of the pickup devices, for repetitively sweeping both the beam of radiation and the image focused on each pickup device across the surface of the article in a second direction, which is orthogonal with the first direction, and in the fixed orientation with each other, to generate electrical signals with the pickup devices in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the images of the incremental areas swept across the surface of the article by the first and second optical deflection devices; a multi-input video display device, having a screen for displaying video information thereon, for receiving at each input a signal from a separate one of the pickup devices and for generating on separate areas of the screen a point image which varies in brightness in accordance with the value of the signal at one of the inputs, and therefore in accordance with the radiation sensed by one of the pickup devices, the point images being in a spatial registry which corresponds with the spatial registry of the images of the incremental areas detected by the pickup devices; first sweep means, coupled with the first optical deflection device, for repetitively sweeping the point images across the screen of the display device in one direction, in synchronism with the sweep of the images focused on the pickup devices across the surface of the article in the first direction; second sweep means, coupled with the second optical deflection device, for repetitively sweeping the point images across the screen in a direction orthogonal to the one direction, in synchronism with the sweep of the images focused on the pickup devices across the surface of the article in the second direction, so that as the point images are swept on the screen the brightness thereof varies in accordance with the intensity of the radiation detected by the pickup devices to display on the screen with each point image a separate visual representation Of the radiation emissivity of the incremental areas of the surface of the article as detected by an associated one of the pickup devices, which separate images together form a composite visual representation of the radiation emissivity of the surface of the article detected by all of the pickup devices.

Claim 11

In a nondestructive apparatus for detecting a thermal characteristic of an article: means for focusing radiation from a source of radiation into a beam for projection onto an incremental area of a surface of the article to heat the area and, by the thermal conduction of the article, to heat the surrounding area; at least three radiation pickup devices, each for sensing the intensity of radiation in a predetermined range of radiation wavelengths and for generating an electrical signal which varies in accordance with the intensity thereof; means for focusing an image of a separate and discrete incremental area of the surface of the article adjacent to the heated area along an optical path and onto each pickup device for detection thereby to generate an electrical signal with each pickup device in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by its detected incremental area; means for intermittently interrupting both the beam of radiation and the optical path to the pickup devices to pulse both the beam of radiation on the surface and the radiation detected by the pickup devices; a first optical deflection device, both in the path of the beam of radiation and in the optical paths of the pickup devices, for repetitively sweeping both the beam of radiation and the image focused on each pickup device across the surface of the article in a first direction and in a fixed orientation with each other; a second optical deflection device both in the path of the beam of radiation and the optical paths of the pickup devices, for repetitively sweeping both the beam of radiation and the image focused on each pickup device across the surface of the article in a second direction, which is orthogonal with the first direction, and in the fixed orientation with each other, to generate electrical signals with the pickup devices in accordance with the intensity of the radiation emitted in the predetermined range of wavelengths by the images of the incremental areas swept across the surface of the article by the first and second optical deflection devices; a multi-input video display device, having a screen for displaying video information thereon, for receiving at each input a signal from a separate one of the pickup devices and for generating on separate areas of the screen a point image which varies in brightness in accordance with the value of the signal at one of the inputs, and therefore in accordance with the radiation sensed by one of the pickup devices, the point images being in a spatial registry which corresponds with the spatial registry of the images of the incremental areas detected by the pickup devices; first sweep means, coupled with the first optical deflection device, for repetitively sweeping the point images across the screen of the display device in one direction, in synchronism with the sweep of the images focused on the pickup devices across the surface of the article in the first direction; second sweep means, coupled with the second optical deflection device, for repetitively sweeping the point images across the screen in a direction orthogonal to the one direction, in synchronism with the sweep of the images focused on the pickup devices across the surface of the article in the second direction, so that as the point images are swept on the screen the brightness thereof varies in accordance with the intensity of the radiation detected by the pickup devices to display on the screen with each point image a separate visual representation Of the radiation emissivity of the incremental areas of the surface of the article as detected by an associated one of the pickup devices, which separate images together form a composite visual representation of the radiation emissivity of the surface of the article detected by all of the pickup devices.

Claim 12

In an apparatus as set forth in claim 8, wherein: each radiation pickup device is a radiometer; the means for intermittently interrupting both the beam of radiation and the optical paths of the radiometers is a multi-bladed chopper, positioned for rotation across both the optical paths of the radiometers and the path of the beam of radiation; the first and second optical deflection devices are first and second plane mirrors, each positioned both in the path of the beam of radiation and in the optical paths of the radiometers, and the mirrors being adapted for oscillating movement in directions which are orthogonal with respect to each other; the multi-input video display device is a multi-gun cathode ray tube, each gun of which is for generating a point image which varies in brightness in accordance with the signal from a separate one of the radiometers; the first sweep means is an x-deflection circuit for sweeping the beam from each gun in an x-direction, and the second sweep means is a y-deflection circuit for sweeping the beam from each gun in a y-direction, the y-direction being orthogonal with respect to the x-direction.

Claim 13

In an apparatus as set forth in claim 9, further including: a first piezoelectric device, coupled to the first plane mirror, for responding to a signal from the x-deflection circuit to impart oscillating movement to the first plane mirror in accordance therewith, and a second piezoelectric device, coupled to the second plane mirror, for responding to a signal from the y-deflection circuit to impart oscillating movement to the second plane mirror in accordance therewith.

Claim 14

In a method of detecting a thermal characteristic of an article: irradiating an incremental area of a surface of the article with a beam of energy to heat the area; detecting the intensity of the thermal response in the same range of radiation wavelengths at at least two discrete incremental areas on the surface of the article adjacent to the heated area; generating a separate electrical signal corresponding to the intensity of the thermal response at each detected incremental area; scanning the heated incremental area and the detected incremental areas across the surface of the article to generate electrical signals which vary in accordance with the intensity of the thermal responses of the detected areas in the same range of radiation wavelengths, and indicating, in accordance with the value of the electrical signals, the thermal responses of the detected incremental areas scanned across the surface of the article.

Claim 15

In a method of detecting a thermal characteristic of an article: irradiating an incremental area of a surface of the article with a beam of energy to heat the area; detecting the intensity of the thermal response in the same range of radiation wavelengths at at least two discrete incremental areas on the surface of the article adjacent to the heated area; generating a separate electrical signal corresponding to the intensity of the thermal response at each detected incremental area; scanning the heated incremental area and the detected incremental areas across the surface of the article to generate electrical signals which vary in accordance with the intensity of the thermal responses of the detected areas in the same range of radiation wavelengths, and indicating, in accordance with the value of the electrical signals, the thermal responses of the detected incremental areas scanned across the surface of the article.

Claim 16

In a method as set forth in claim 11, wherein: the scanning step includes scanning the heated incremental area and the detected incremental areas, in a fixed spatial relationship with respect to each other, across the surface of the article in a predetermined path, and the indicating step includes generating separate visual images, each of which is representative of the intensity of the thermal response detected at an individual one of the incremental areas scanned across the surface of the article, and each of which varies in brightness in accordance with the thermal responses of the detected incremental area, which separate images, taken together, form a composite image representative of the intensity of the thermal response at all of the scanned incremental areas.

Claim 17

In a method of nondestructively determining a thermal characteristic of a workpiece: focusing a beam of radiant energy onto an incremental area of a surface of the workpiece to heat the area and, by the thermal conduction of the workpiece, to heat the area adjAcent to the incremental heated area; focusing an image of each of at least two discrete incremental areas on the surface of the workpiece onto a separate heat detection device; generating an electrical signal, with each heat detection device, which is in accordance with the intensity of the thermal response in a predetermined range of radiation wavelengths of the incremental area the image of which is detected thereby, the intensity of the thermal response of each incremental area in the predetermined range of wavelengths being a function of the internal structure of the workpiece at and adjacent to the incremental area; intermittently interrupting both the focused beam of radiant energy and the focused images of the incremental areas to pulse the beam on the incremental heated area of the surface and to pulse the image focused onto each heat detection device; repetitively scanning both the focused beam and the focused images across the surface of the workpiece in a predetermined pattern and in a fixed spatial relationship with each other to generate electrical signals with the heat detection devices which vary in accordance with the intensity of the thermal responses of the detected incremental areas in the predetermined range of wavelengths; forming a separate variable brightness point image on a screen, for each detected incremental area, which is in the same spatial relationship with respect to the other point images as is that detected incremental area with respect to the other detected incremental areas; varying the brightness of each point image in accordance with the electrical signal generated by the heat detection device onto which is focused the image of the incremental area for which the point image is formed; scanning the point images across the screen in the predetermined pattern, and in synchronism with the scanning of the focused images across the surface of the workpiece, to form on the screen a separate visual representation of the thermal response of the surface of the workpiece as detected by each heat detection device, which separate visual representations, taken together, form a composite visual representation of the thermal response of the surface as detected by all of the heat detection devices.

Claim 18

In a method of nondestructively determining a thermal characteristic of a workpiece: focusing a beam of radiant energy onto an incremental area of a surface of the workpiece to heat the area and, by the thermal conduction of the workpiece, to heat the area adjAcent to the incremental heated area; focusing an image of each of at least two discrete incremental areas on the surface of the workpiece onto a separate heat detection device; generating an electrical signal, with each heat detection device, which is in accordance with the intensity of the thermal response in a predetermined range of radiation wavelengths of the incremental area the image of which is detected thereby, the intensity of the thermal response of each incremental area in the predetermined range of wavelengths being a function of the internal structure of the workpiece at and adjacent to the incremental area; intermittently interrupting both the focused beam of radiant energy and the focused images of the incremental areas to pulse the beam on the incremental heated area of the surface and to pulse the image focused onto each heat detection device; repetitively scanning both the focused beam and the focused images across the surface of the workpiece in a predetermined pattern and in a fixed spatial relationship with each other to generate electrical signals with the heat detection devices which vary in accordance with the intensity of the thermal responses of the detected incremental areas in the predetermined range of wavelengths; forming a separate variable brightness point image on a screen, for each detected incremental area, which is in the same spatial relationship with respect to the other point images as is that detected incremental area with respect to the other detected incremental areas; varying the brightness of each point image in accordance with the electrical signal generated by the heat detection device onto which is focused the image of the incremental area for which the point image is formed; scanning the point images across the screen in the predetermined pattern, and in synchronism with the scanning of the focused images across the surface of the workpiece, to form on the screen a separate visual representation of the thermal response of the surface of the workpiece as detected by each heat detection device, which separate visual representations, taken together, form a composite visual representation of the thermal response of the surface as detected by all of the heat detection devices.

Claim 19

In a noncontacting apparatus for generating a thermal image of an article: means for incrementally heating discrete areas of a surface of the article; a pair of heat detector means, each for separately sensing the thermal radiation response in the same range of radiation wavelengths from an individual one of two discrete positions relative to the discrete heated areas and for generating signals in accordance therewith, and means responsive to the signals for displaying a thermal image of the article.

Claim 20

In a noncontacting apparatus for generating a thermal image of an article: means for incrementally heating discrete areas of a surface of the article; a pair of heat detector means, each for separately sensing the thermal radiation response in the same range of radiation wavelengths from an individual one of two discrete positions relative to the discrete heated areas and for generating signals in accordance therewith, and means responsive to the signals for displaying a thermal image of the article.

Claim 21

In an infrared scanning apparatus for detecting a thermal response of an article: means for focusing a beam of infrared radiation onto an incremental area of a surface of the article to heat the incremental area and, through thermal conduction, to heat incremental areas of the article surrounding the heated incremental area; three infrared radiation detecting devices, each for receiving infrared radiation and for generating an electrical signal which varies in accordance with the intensity of the received radiation which is in a predetermined range of radiation wavelengths; means for focusing each radiation detecting device along an optical path and onto a separate and discrete incremental area on the surface of the article adjacent to and externally of the heated area to detect the radiation emitted by each conductively heated incremental area and to generate from each detecting device an electrical signal which varies in accordance with the intensity of the radiation emitted in the predetermined range of radiation wavelengths by the incremental area onto which the detecting device is focused, the centers of the detected incremental areas being successively positioned at 90* increMents with respect to the center of the heated incremental area; means for scanning both the beam of radiation and the optical paths of the radiation detecting devices across the surface of the article in a predetermined pattern, with the heated incremental area and the detected incremental areas maintained in a fixed spatial orientation with respect to each other and with not more than one of the radiation detecting devices detecting incremental areas of the surface which are scanned by the beam of radiation, to generate an electrical signal from each detecting device which varies in accordance with the intensity of the radiation in the predetermined range of radiation wavelengths emitted from the scanned incremental areas onto which the detecting device is focused; a three gun cathode ray tube, each gun of which receives the electrical signal from an individual one of the radiation detecting devices and generates on the screen of the tube a point image which varies in brightness in accordance with the signal, the three guns together generating three discrete point images on the screen of the tube in a spatial orientation corresponding to the spatial orientation of the three detected incremental areas, and means for scanning the three point images across the screen of the tube in the predetermined pattern in a fixed spatial orientation with respect to each other and in synchronism with the scan of the three detected incremental areas across the surface of the article in the predetermined pattern, to generate with each point image a separate raster image representative of the radiation in the predetermined range of radiation wavelengths detected by an individual one of the detectors, the three separate images together forming a composite raster image of the radiation in the predetermined range of wavelengths detected by the three detectors.

Claim 22

In an infrared scanning apparatus for detecting a thermal response of an article: means for focusing a beam of infrared radiation onto an incremental area of a surface of the article to heat the incremental area and, through thermal conduction, to heat incremental areas of the article surrounding the heated incremental area; three infrared radiation detecting devices, each for receiving infrared radiation and for generating an electrical signal which varies in accordance with the intensity of the received radiation which is in a predetermined range of radiation wavelengths; means for focusing each radiation detecting device along an optical path and onto a separate and discrete incremental area on the surface of the article adjacent to and externally of the heated area to detect the radiation emitted by each conductively heated incremental area and to generate from each detecting device an electrical signal which varies in accordance with the intensity of the radiation emitted in the predetermined range of radiation wavelengths by the incremental area onto which the detecting device is focused, the centers of the detected incremental areas being successively positioned at 90* increMents with respect to the center of the heated incremental area; means for scanning both the beam of radiation and the optical paths of the radiation detecting devices across the surface of the article in a predetermined pattern, with the heated incremental area and the detected incremental areas maintained in a fixed spatial orientation with respect to each other and with not more than one of the radiation detecting devices detecting incremental areas of the surface which are scanned by the beam of radiation, to generate an electrical signal from each detecting device which varies in accordance with the intensity of the radiation in the predetermined range of radiation wavelengths emitted from the scanned incremental areas onto which the detecting device is focused; a three gun cathode ray tube, each gun of which receives the electrical signal from an individual one of the radiation detecting devices and generates on the screen of the tube a point image which varies in brightness in accordance with the signal, the three guns together generating three discrete point images on the screen of the tube in a spatial orientation corresponding to the spatial orientation of the three detected incremental areas, and means for scanning the three point images across the screen of the tube in the predetermined pattern in a fixed spatial orientation with respect to each other and in synchronism with the scan of the three detected incremental areas across the surface of the article in the predetermined pattern, to generate with each point image a separate raster image representative of the radiation in the predetermined range of radiation wavelengths detected by an individual one of the detectors, the three separate images together forming a composite raster image of the radiation in the predetermined range of wavelengths detected by the three detectors.