FR2604587A1 - VIDEO DISPLAY APPARATUS WITH IMAGE OVERLAY - Google Patents

Abstract

THE INVENTION RELATES TO A DISPLAY DEVICE FOR FORMING OVERLAPPED IMAGES. IT RELATES TO AN APPARATUS IN WHICH A VIDEO CAMERA 16 GIVES AN IMAGE OF AN OBJECT 11 TO BE STUDY. A SENSOR 13 DETERMINES A CHARACTERISTIC OF THE OBJECT TO BE STUDIED AND, WHEN THIS CHARACTERISTIC HAS A DETERMINED VALUE, A LIGHT SOURCE 15 IS ILLUMINATED. A MICROCOMPUTER 18 DETERMINES THE PRESENCE OF THIS SIGNAL BECAUSE IT EXCEEDS A THRESHOLD VALUE AND ADDS IT TO THE CAMERA SIGNAL ON A COLOR MONITOR 31. APPLICATION TO NON-DESTRUCTIVE CONTROL OF STRUCTURES.

Description

The present invention relates to a device

  to form a video display in which an image obtained from one or more detector systems is superimposed on a visible image from a camera. In this way, a user of the apparatus can be helped by obtaining a relationship between the output signal of a non-visible signal detector and the visible aspect of the image of an object.

studied, obtained with the camera.

  Although extremely elaborate techniques

  image processing and manipulation are available.

  computers and microprocessors, a problem posed by the above-mentioned type of image overlay is that of the relative positioning of one image with respect to the other, with the

  appropriate layout and scale.

  British Patent No. 2,136,242 discloses a solution to this problem involving a display video signal generating apparatus capable of controlling a suitable imaging system which creates superimposed images from at least two systems. detectors, the apparatus comprising a camera, one or more detector systems, the detector system or at least one detector system comprising a moving probe, a source mounted on the probe, the position of the source being representative of the position of the detector, study of the associated detector system,

  that source emitting light or other

  the camera is sensitive, beyond a predetermined intensity, whenever the

  detected by the detector system associated with a character

  predetermined, the camera, when moved in an area including the study position, giving a video signal which contains the one that is formed by light or radiation of another type from the source carried by the probe , a detector

  threshold for detecting whether light or

  another type, received by the camera, exceeds the

  said predetermined intensity, a memory system,

  lysed in synchronism with the video signal from the camera and for storing the video signal at all positions at which the predetermined intensity is exceeded, and a device for mixing the video signals from. of the memory system and the video signals from the camera, so that the mixed signals, when transmitted to an imaging system, are displayed as a

  visible image seen by the camera, with bright dots

  Limes superimposed at all positions of the image

  the predetermined intensity has been exceeded.

  The present invention is a refinement

  of that described in the British patent

  cited in No. 2,136,242, and relates to a general apparatus

  a video display signal capable of controlling a suitable image formation system for forming superimposed images, the apparatus comprising a video camera, one or more detector systems, the detector system or a detector system at least among several comprising a moving probe, a source mounted on the probe, the position of the source being representative of a study position of the associated detector system, the source emitting light or radiation of another type to which the camera is

  sensitive, this radiation or light having a characteristic

  distinguishing feature, the camera, when placed on an area including the study position, forming an image video signal that includes the one produced

  by the light or radiation of another type.

  from the source placed on the probe, a memory system, a device for analyzing the memory system

  in synchronism with the image video signal, an arrangement

  controlled by the distinguishing characteristic and intended to give an identification of the address, in the memory system, of the position of the probe, a device intended to function independently of the distinctive characteristic, under the control of the detector system and intended to causing the memory system to store, at said identified address, a representation of the output signal of the detector system at the position of the probe corresponding to the identified address, and a device for combining video signals of image from the camera to video signal elements derived from the memory system so that the combined signals, when transmitted to an imaging system, are displayed as a visible image as seen by the camera with superimposed image elements that are representative of the output signal of the detector system

at the study positions of the probe.

  The device controlled by the detector system can trigger the memory system whenever the

  the output signal of the detector system has a characteristic

  predetermined range so that data representing

  both a predetermined element of video signal are kept at said identified address in the memory system, corresponding to the position of the probe, so that the combined signals, when transmitted to an imaging system, are displayed in the form of a visible image seen by the camera, with the predetermined superimposed image elements in all the study positions of the probe for which

  the detector system gave an output signal

  both said predetermined characteristic.

  In this way, the use of a camera that is sensitive to visible light and a light source placed on the probe allows the probe to move over an object and form a point arrangement. shiny superimposed on the ordinary visible image of the object, the bright dots corresponding to certain predetermined characteristic studied. For example, the detector system may be as described in British Patent No. 2,044,198 in which backscattered penetrating radiation is detected, for example in the form of neutrons destined to. reveal the presence of a low atomic number matter hidden behind steel. Additional sensor systems may be present, each including a probe that carries a light source. In this case, it is desirable for one detector system to be distinguished from another by

  use of light sources of different colors

  annuities, on different probes. In addition, the indica-

  the response of a single detector system can be subdivided by providing, on the probe, a plurality of light sources that can be distinguished

  from each other by their color differences.

  In some applications, it is possible that the display

  display is only desired for images obtained by scanning the probes of two or more detectors,

  without incorporating the display of the visible scene.

  In this case, the camera can be adjusted so that

  only be sensitive to the brightness of the light sources

  sensors carried by the probes and that it does not form an image from other light sources: In a first arrangement according to the invention, the distinctive feature is the intensity of

  light or radiation of another type, when

  it exceeds a predetermined intensity. In this

  case, the device sensitive to the distinctive characteristic

  tive has a threshold detector. It should be noted that the intensity of light or radiation of another type, coming from the source, must exceed that of the radiation coming from any other object present in the scene observed by the camera.

  position indications of the source are avoided.

  In another arrangement according to the invention, the distinctive feature is that the light or radiation of another type, from the source, flashes or modulates in a predetermined manner, and the characteristic-responsive device distinctive is sensitive to blinking

or modulation.

  The predetermined video signal element advantageously has a first characteristic, for example a green color, when the output signal of the detector system has a first characteristic, for example representative of the absence of a fault, and the predetermined element of video signal. to another

  characteristic, for example a red color,

  that the output signal of the detector system has another characteristic, for example representative of the presence of a defect. When a detector system can provide a range of output signals, representative of a corresponding range of property to which the sensor system is responsive, a corresponding range of characteristics, e.g.

  in the form of a gray scale, of the predetermined element

  video signal, can be created.

  Preferably, the memory system and the

  positive analysis of this system include a micro-

  computer. Synchronism with the video camera is

  obtained by connecting a synchronization output signal

  the microcomputer to a sync signal input of the camera so that the scanning

  the camera is provided in synchronism with the general

  video signal display of the microcomputer.

  A particular apparatus construction according to the invention is now described by way of illustration and with reference to the appended drawings whose figure

  unique is a block diagram of the device.

  The single figure shows an apparatus for superimposing, on an image of a visible scene, an image obtained by means of a non-visible signal detector, an ultrasonic inspection system in the

case considered.

  A sample studied is designated by the

  reference 11. A conventional system of ultra-long inspection

  sound comprises a probe 13 and transmits an output signal through a line 14. In a simple arrangement, this output signal is in digital form and has a first level (1) when the system detects a defect

  in the inspected area, and another level (0) when

no fault is detected.

  The probe 13 is modified, in the example in question, by mounting a point light source which is permanently switched on during the

duration of the study.

  A monochrome video camera 16 receives

  synchronization signals by a line 17, from

  The output signal of the camera 16, representing the intensity of each image point of the raster scan sequence, is transmitted by a line 19 to a threshold detector 21 and a network 22. thanks to which the modulated monochrome signal

  intensity is applied by semiconductor switches

  conductors 23, 24, 25 with three lines 26, 27, 28 respectively.

  connected to the red, green and blue inputs

  RGB of the monitor 31 in color. As is clear from

  the following description, the synchronization signal

  17, with the R, G, B signals of the lines 26, 27, 28, all of which are transmitted to the color monitor 31, form a composite input signal forming a color video image, in accordance with FIG.

  standard format, for the 31 color monitor.

  The semiconductor switches 23, 24, 25 are respectively controlled by the output signals R, V, B of the microcomputer as indicated by the lines 32, 33, 34. The associated switch 23 is closed when the line 32 transmits a signal and is open when the signal is at a predetermined low level. The switches 24, 25 operate in the same way,

  for the signal levels of lines 33 and 34 respectively

  tively. A converter of the television-X-Y type is intended to give X, Y coordinates representing a

  position intended for a microcordinal memory system.

  from the TV screen raster signal.

  if we. A synchronization signal for the converter 35 is transmitted through line 17 and the output signals of line 36, transmitted to microcomputer 18, combined with those of line 14, from the ultrasonic inspection system, form microcomputer data input signals 18. The operation of the

  converter 35 is produced under the control of the detector.

threshold transmitter 21.

  During operation, the intensity of the

  light from the source 15 is set to a value exceeding

  any other object in the field

of vision of the camera 16.

  Initially, all semiconductor switches

  23, 24, 25 are closed so that the monitor 31 displays a black and white image corresponding to the visible scene observed by the camera 16. However, when the scanning of the camera reaches the image of the point source 15, the light intensity is such that the level of the signal in the line 19 exceeds the threshold set by the detector 21. The operation triggers the converter 35 which transmits to the microcomputer 18, via the line 36, the address of the location of the memory of the computer that corresponds to the position of

  the image of the point source 15, at this moment.

  In this example, the microcomputer 18 is programmed to hold at this address data from line 14 in a form such that the output signals of lines R, V and B, 32, 33, 34, from the microcomputer, have the following effect for all subsequent scans until the data at that memory address is changed or deleted:

  1. in the absence of a fault signal in the

  14, the switches 23 and 25 are open and the switch 24 is closed, 2. in the presence of a fault signal in the line 14, the switches 24 and 25 are open and the switch 23 is closed. The consequence is that the image point or the image points of the display corresponding to one or more positions of the point source 14 is displayed or are displayed in green in the absence of a signal

  fault and in red in the presence of a fault signal.

  When the probe 13 is then moved so that it ensures for example a scanning inspection of the sample 11, each new position is "painted" on the display device, the green indicating the places where the inspection was carried out and o no defects were found, and the red indicating the locations

o defects have been found.

  In this example, the computer is programmed so that when the probe 13 scans a region more than once, the green display may be red but not vice versa. Thus, the detection of a fault is indicated in red on the display even if an earlier scan of the same zone did not reveal the presence of a fault. However, when a fault has been detected, the associated red display can not

be given in green form.

  It should be noted that the arrangement as described operates with any type of detector system having an output signal in binary form or by

all or nothing.

  However, the flexibility of a microordinate can be easily implemented so that it gives

more elaborate possibilities.

  Thus, a detector system giving a range of six different characteristics of the output signals can be easily used in the described arrangement, by switching allowing the creation of

  green, red, blue, red-green, red-blue, green-

  depending on the characteristic of the signal received from the

tor.

  For example, the ultra-light inspection system

  sound may give an indication that the coupling between the probe 13 and the sample 11 is satifaisant or not. A signal indicating poor coupling may thus give rise to a particular color constituting a warning to the operator and indicating sample regions in which the analysis is to be performed.

to be repeated.

  In the case of a larger elaboration in which a greater number of characteristics of the detector output signals can be used, a signal intensity mixing process from the computer's R, G, B outputs and those coming from the video camera must be

  introduced, instead of a simple switch.

  A problem that sometimes arises with the apparatus of this example is due to the fact that the threshold level set by the detector 21 is exceeded by the appearance of a glossy object which has no connection with

  the probe 13, in the field of view of the camera 16.

  One solution to this problem is the periodic detection

  automatic setting of the maximum intensity of the image when the point source 15 is extinguished and the restoration of the intensity of the point source, by switching it back on, to a value greater than the determined maximum value. The threshold detector 21 must obviously be delivered simultaneously at a level greater than the maximum value and less than

  the new value of the intensity of the source

15.

  Another solution is the use of a variant in which the point source 15 flashes all or nothing, in synchronism with each successive scan of a frame. The threshold detector 21 is removed and the microcomputer 18 is programmed to record the points of the image that are switched.

  by all or nothing in sync with the scanning of the image.

  The invention is not limited to the details of the previous example. Other detector systems may be used, for example using penetrating radiation or eddy currents. In fact, the device can be used with any

  which detector system whose response can be

  -mitted in restricted areas, determined by a probe position or by a probe and the position

an associated point source.

  As described in British Patent No. 2,136,242, the use of one or more lenses and / or one or more mirrors may be convenient for obtaining a desired apparent or geometric position.

of the point source.

  The arrangement can be easily adapted so that it can be used with a camera that is sensitive to radiation other than radiation

  visible. Thus, a camera sensitive to infra-

  red can be used for example. When the camera is also sensitive to visible light, as is

  usually the case, a diode emitting in the infra-

  red can be used as a source placed on the probe. The intensity of the infrared radiation emitted by the diode must be such that it exceeds a predetermined reference value. In a variant, an infrared camera can obviously allow the formation of a general image of a scene (for example at night) which is not lit by visible light but emits infrared. In this case, the source carried by the probe can also be a diode emitting in the infrared or can be a light source

visible.

  The composite video output signal can be recorded on a VCR so that it can be displayed through a monitor later. The composite video signal can be transmitted over long distances by cable or radio transmission

where appropriate.

  In a refinement, the initial setting of the camera's diaphragm and the intensity of the

  source carried by the probe is facilitated by

  additional levels of output signals

  of the camera and by a command provided by a software.

  Thus, for example, based on software-controlled instructions displayed on the screen, the operator must adjust the camera's iris, when the probe source is not on, until the maximum intensity of the image signal (the brightest object of the visible scene) exceeds 50% of the maximum signal (saturation) that the camera can transmit, but is less than 70% of this maximum signal. The source of the probe is then lit and its intensity is gradually increased until it gives an output signal whose inzensity corresponds to 95% of

the maximum value of the camera.

Claims (7)

  1. Apparatus generating a video display signal, capable of controlling a suitable system of   image formation for forming superimposed images   posed, the apparatus being characterized in that it comprises   a video camera (16), one or more detection systems   sensors (12), the detector system or at least one of the detector systems comprising a moving probe (13), a source (15) placed on the probe, the position of this source being representative of a study position of the associated detector system, this source forming light or radiation of another type to which the   camera is sensitive, this radiation having a characteristic   the camera (16), when it is moved over an area of said study position, forming a video image signal containing the one formed by the light or radiation of another type from the source on the probe, a memory system, a device (18) for analyzing the memory system in synchronism with the video image signal, a device (21) responsive to the distinctive feature and for give an identification of the address of the position of the probe in the memory system, a device operating independently of the distinctive feature, under the control of the   detector system, and intended to provoke   in the memory system and at the address identi-   a representation of an output signal from the   detector system at the position of the probe corresponding to   to the identified address, and a device (22) for combining the video image signals from the camera with the video signal elements from the memory system, so that the combined signals, when transmitted to a system of image formation, are displayed in the form of the visible image seen by the camera with superimposed image elements representative of an output signal of the detector system at the study positions of the probe.   2. Apparatus according to claim 1, characterized   in that the device controlled by the detector system (12) triggers the memory system whenever the output signal of the detector system has a predetermined characteristic so that it stores at the address identified in the memory system. which corresponds to the position of the probe, data representing a predetermined element of video signal, -if the combined signals, when   transmitted to an imaging system, are displayed   in the form of the visible image seen by the camera (16) with predetermined superimposed image elements at all the study positions of the probe (13) for which the detector system has transmitted a signal of   output having the predetermined characteristic.   3. Apparatus according to one of claims 1 and   2, characterized in that the distinguishing characteristic is the intensity of the light or radiation of a   other type, when it exceeds a predetermined intensity   mined, and the feature-sensitive device   distinctive comprises a threshold detector (21).   4. Apparatus according to one of claims 1 and   2, characterized in that the distinguishing characteristic is such that light or radiation of another type, from the source, is flashing or is modulated in a predetermined manner, and the device sensitive to   the distinctive feature is sensitive to blinking or modulation.   5. Apparatus according to claim 2, characterized   in that the predetermined video signal element has a first characteristic, when the signal   of the detector system (12) has a first characteristic   characteristic, and the predetermined video signal element has another characteristic when the output signal   of the detector system has a second characteristic.   Apparatus according to claim 2, characterized   in that a detector system (12) is intended for   transmit a whole range of output signals   sensing of a corresponding range of the property to which the sensor system is responsive, and a corresponding range of features of the element   predetermined video signal is created.   Apparatus according to any of the claims   the memory system and the memory system analysis device comprise a microcomputer (18), and the synchronism with the video camera (16) is obtained by transmission.   an output synchronization signal from the microordinate   to a synchronization signal input of the camera, so that the scanning of the camera is ensured in synchronism with the display signal generator video of the microcomputer.