Method and device for monitoring the attentiveness of an operating person

Abstract

The invention relates to a method and corresponding devices for monitoring the attention of an operator of an X-ray inspection system for nondestructive inspection of inspection objects and for ensuring the presence and/or attention of an operator of the X-ray inspection system including the following steps: display of a piece of information that defines a randomly determined desired input; detection of an actual input of the operator as a response to the displayed desired input; and, based on the desired input and the actual input, determination of a signal that indicates the attention of the operator.

Claims

1. A method for monitoring the attention of an operator of an X-ray inspection system, the X-ray inspection system configured to nondestructively inspect at least one object, the method comprising: displaying a randomly generated desired operator input on a display unit of a workstation of the X-ray inspection system and displaying X-ray inspection imaging only for the at least one object nondestructively inspected by the X-ray inspection system, the displayed desired operator input corresponding to a randomly selected position on the display unit; determining whether an actual operator input responsive to the displayed desired operator input has been received via a user input device of the workstation of the X-ray inspection system at a processor of the workstation of the X-ray inspection system, the actual operator input including, at least in part, a corresponding operator input position on the display; comparing the received actual operator input with the desired operator input based on the determination at the processor of the workstation of the X-ray inspection system, the comparison including matching the corresponding operator input position on the display with the randomly selected position on the display unit, the desired operator input indicated on the display unit and the received actual operator input received via the user input device needing to match to be deemed a correct attentive response by the processor of the workstation of the X-ray inspection system; and generating a signal indicative of attentiveness of the operator based on the comparison at the processor of the X-ray inspection system, an inattentive signal generated when there is not a correct attentive response, the inattentive signal triggering a command to bring the system into a predetermined safe state, the predetermined safe state including a stoppage in actuation of the X-ray inspection system.

2. The method according to claim 1, further comprising: determining as to whether the actual operator input is received within a predetermined time following the display of the desired operator input.

3. The method according to claim 1, further comprising: displaying the randomly generated desired operator input quantitatively in one of a graphical format and an alphanumeric format; receiving the actual operator input via an actuation device; and comparing the actual operator input received via the actuation input device to the desired operator input.

4. The method according to claim 3, further comprising: displaying the actual operator input received via the actuation input device on the display unit.

5. A device for monitoring the attention of an operator of an X-ray inspection system, the X-ray inspection system configured to nondestructively inspect at least one object, said device including: a processing unit configured to randomly generate a desired operator input; a display unit communicatively coupled to the processor and configured to display the randomly generated desired operator input, the displayed desired operator input corresponding to a randomly selected position on the display unit, the processing unit and the display unit together configured to display X-ray inspection imaging only for the at least one object nondestructively inspected by the X-ray inspection system; and an input device communicatively coupled to the processor and configured to receive an actual operator input responsive to the display of the desired operator input, the actual operator input including, at least in part, a corresponding operator input position on the display, and wherein the processing unit is further configured to: compare the received actual operator input with the desired operator input, the comparison including matching the corresponding operator input position on the display with the randomly selected position on the display unit, generate a signal indicative of attentiveness of the operator based on the comparison, and issue a command to a control unit of the X-ray inspection system to place the X-ray inspection system in a pre-determined safe state based on the comparison, the predetermined safe state including a stoppage in actuation of the X-ray inspection system.

6. The device according to claim 5, wherein the processing unit is further configured to determine whether the actual operator input is received within a predetermined time interval following the display of the desired operator input.

7. The device according to claim 5, wherein the display unit comprises a screen and the input device comprises a keyboard.

8. The device according to claim 5, wherein the processing unit is further configured to: display randomly generated desired operator input in one of graphical format and an alphanumeric format, receive the actual operator input via an actuation input device, and compare the actual operator input received via the actuation input device to the desired operator input.

9. The device according to claim 8, wherein the processing unit is further configured to display the actual operator input via the actuation input device in one of a graphical format and an alphanumeric format on the display unit.

10. The device according to claim 5, wherein the input device comprises an actuating input device that can be gradually actuated to generate the actual operator input.

11. The device according to claim 10, wherein the actuating input device comprises: a pressure sensor; and an actuating element coupled to the pressure sensor configured to generate actual values associated with the actual operator input from a predetermined value range.

12. The device according to claim 5, wherein the display unit and input device comprise at least one of a touch-sensitive screen and a keypad.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other advantages, features, and details of the present disclosure ensue from the following description in which embodiments of the present disclosure are described in detail with reference to the drawings. In this connection, the features mentioned in the claims and in the description can each be intrinsically essential to the present disclosure by themselves or in any combination with one another. The features mentioned above and explained again in greater detail here can each be used by themselves or can be used in any combination with one another. Some parts or components that are functionally similar or identical have been provided with the same reference numerals. The terms “left,” “right,” “top,” and “bottom” used in the description of the embodiments refer to the drawings in an orientation in which the figure name and/or reference numerals can be read in the normal way. The embodiments shown and described are understood not to be exhaustive, but instead to have an exemplary character for the explanation of the present disclosure. The detailed description is provided in order to inform the person skilled in the art and therefore the description does not illustrate or explain known circuits, structures, and methods in detail in order not to complicate the comprehension of the present description.

(2) FIG. 1 shows a first embodiment of a monitoring device with a display unit and a separate input device.

(3) FIG. 2 shows a second embodiment of a monitoring device with a combined display unit/input device in the form of a touch screen.

(4) FIG. 3 shows a third embodiment of a monitoring device with an input device in the form of a keypad that has a display element.

(5) FIG. 4 shows another embodiment of a monitoring device with a touch screen as a combined input/output device.

(6) FIG. 5 shows a fifth embodiment of a monitoring device with a combined display unit/input device in the form of a touch screen.

(7) FIG. 6 shows a flow chart of an embodiment of a monitoring method.

DETAILED DESCRIPTION

(8) FIG. 1 shows a schematic block diagram of a first embodiment of a monitoring device for monitoring the attention of an operator of an apparatus. The apparatus can be a system or a machine whose operation requires the assurance that an operator is paying attention.

(9) A processing unit 110 is connected to a display unit 112 for displaying alphanumeric and graphic information in the way known from computer screens. The display unit can thus be any screen such as an LCD-, TFT-, LED-, OLED-, or plasma screen. The processing unit 110 is also connected to an input device 118, which is a known, commercially available keyboard of the kind known from computer workstations.

(10) In order to implement a method for monitoring the attention of the operator of the apparatus, the processing unit 110 is configured to show the layout of the keyboard, i.e. the input device 118, at irregular intervals on the screen in the form of a graphic representation 114 of the keyboard layout on the display 112.

(11) The processing unit 110 is also configured to generate a piece of information that defines a randomly determined desired input for the operator. To this end, in the present exemplary embodiment, a random generator of the processing unit 110 determines a key of the keyboard layout of the input device 118.

(12) The randomly determined key is displayed on the display unit 112—in the keyboard layout 114 shown there—as a key 116 that is optically highlighted relative to the other keys, for example the “T” key. This randomly determined and optically highlighted key 116 therefore corresponds to the information that is shown to the operator and with which a desired input for the operator is defined. The key 116 can, for example, be optically highlighted by means of a different color or brightness. It is also possible for the key 116 to be marked with a flashing effect, for example in that the color of the key regularly alternates between two or more colors and/or brightness values.

(13) Once the randomly selected key 116 is displayed, a timer in the processing unit 110 is started, which defines a predetermined time window within which the operator must complete an input.

(14) The operator, using the keyboard as an input device 118, can then press the key 116 shown on the display unit 112 in order to confirm that he is paying attention. An input by the operator that is completed within the time window being monitored with the timer, i.e. the pressing of the key 120, corresponds to the actual input by the operator as a response to the displayed desired input. In the case shown, the operator presses the “G” key.

(15) The processing unit 110, which is operatively connected to the display unit 112 and the input device 118, is configured to compare the desired input (in this case the “T” key) on the display unit 112 to the actual input (in this case the “G” key) made by the operator.

(16) If the key shown on the display unit 112 coincides with the key 120 pressed on the input device 118 within the permissible time interval, then the processing unit 110 evaluates this as a positive confirmation by the operator that he is paying attention and generates a corresponding signal that shows that the operator is paying attention.

(17) In the case shown in FIG. 1, the operator has pressed the incorrect key, namely the “G” key instead of the correct key (the “T” key). The processing unit interprets this as an indicator that the operator is not paying attention and generates a corresponding signal indicating operator's attention level. The same conclusion is reached if the operator does not complete an input within the permissible time interval.

(18) The first embodiment is suitable for being implemented solely by software means on already existing workstations of an operator similar to a known computer workstation. The function of the processing unit 110 is particularly easy to integrate in the form of a software routine into the operating system level and the above-described steps for monitoring the attention of the operator are implemented by means of the screen as the display unit and the keyboard as the input device that are present in such a workstation anyway.

(19) FIG. 2 shows a second embodiment of the monitoring device, which essentially corresponds to the first embodiment. The essential difference lies in the fact that the display unit and input device are combined in the form of a touch screen 212, i.e. a touch-sensitive screen.

(20) The processing unit 210 is connected to the touch screen 212 serving as a combined display/input device. In order to implement the monitoring of the operator's attention, in this case, analogous to the exemplary embodiment in FIG. 1, a keyboard layout 214 in any graphic form is displayed. In addition to the keyboard layout 214, the processing unit 210 shows a key identification 216—for example “T”—as the information that defines a randomly determined desired input. In other words, the displayed key identification 216 determines the desired input for the operator.

(21) In order to confirm that he is paying attention, the operator is then required, as an input, to touch the surface of the touch screen 212 on the displayed keyboard layout 214 at the location that corresponds to the “T” key.

(22) As discussed in connection with the embodiment in FIG. 1, a key 220, which the operator has identified by touching the touch screen 212 in the keyboard layout 214 with a finger, is then detected by the processing unit 210 and can thus be compared to the randomly determined desired input.

(23) In the example shown, the touching of the key 220 labeled “T,” as the actual input of the operator, corresponds to the expected desired input. The processing unit 210 interprets this as a positive indication that the operator is paying attention and correspondingly generates the signal that corresponds to the operator paying attention.

(24) In reverse circumstances, i.e. if the operator does not complete the input on time, does not make an input at all, or touches the incorrect location on the touch screen 212, then the processing unit 210 generates a correspondingly negative signal for the operator's attention.

(25) FIG. 3 shows a third embodiment for a device for monitoring the attention of an operator. In a modification relative to the first and second embodiments, there is no display unit in the conventional sense. The display unit is configured in the form of display elements that are integrated into a keypad 318 serving as the input device.

(26) For example, the keypad can be a numerical keypad with numbers for the keys 0 through 9. A display element is any key with an illuminated ring 312, which is made of a light-conducting plastic, for example, which can be occasionally illuminated or not by means of an internally installed light source.

(27) The processing unit 310 then uses a random generator to determine one of the keys 0 through 9, for example the key 320 labeled “7,” as the randomly determined desired input for the operator. The randomly determined desired input, namely the key 320, is displayed by means of a display element 312 integrated into the keypad 318 in that the ring 316 encompassing the key 320 is illuminated. In other words, the illumination of the ring 316 shows the operator the information that indicates the randomly determined desired input, namely the “7” key.

(28) The operator can then once again—in a way similar to that used in the exemplary embodiments shown in FIGS. 1 and 2—make an input within a predetermined time window by pressing one of the keys on the keypad 318.

(29) Assuming that the operator presses the key 320 in time, this is then detected by the processing unit 310, which is connected to the keypad 318. Correspondingly, the processing unit 310, which is coupled to the display means 312 functioning as the display unit and coupled to the keypad 318 functioning as the input device, can compare the actual input, i.e. the key 320 pressed by the operator, to the desired input, i.e. the displayed key 320. Based on the comparison result, the processing unit 310 then generates the signal that indicates the attention of the operator. In the present case, the operator has been shown the “7” key and the operator has pressed the “7” key within the required time interval so that the processing unit 310 has generated a positive signal for the attention of the operator.

(30) FIG. 4 shows a fourth embodiment of a device for monitoring the attention of the operator. Similar to the embodiment in FIG. 2, the processing unit 410 is operatively connected to a touch screen 412 functioning as a combined display/input device.

(31) In order to monitor the attention of the operator, the processing unit 410 first randomly generates coordinates of a touchable location on the touch screen 412. These randomly determined coordinates define a location on the touch screen 412 as a randomly determined desired input, which an operator is supposed to touch in order to confirm that he is paying attention.

(32) To show the operator this randomly determined desired input, the processing unit 410 displays the desired input in the form of a symbol 416 appearing at the randomly determined location on the touch screen 412. In the exemplary embodiment, the symbol 416 is an X that identifies the location. This can also be any other symbol, for example a circle, a square, or simply a dot. The symbol should essentially be able to identify a location on the touch screen, which is to be touched, with sufficient precision for the method described here.

(33) Once the symbol 416 is shown on the touch screen 412, the processing unit 410 once again monitors the time window within which the operator is supposed to touch the location on the touch screen 412 that is identified with the symbol 416.

(34) The touch screen 412 simultaneously functioning as a display unit and input device detects the location at which the operator touches the touch screen 412 and reports the coordinates of the location that has been touched back to the processing unit 410. The processing unit 410 compares the coordinates of the desired input to the coordinates of the actual input. Based on the comparison result, the signal representing the attention of the operator is once again generated.

(35) Since the touching of a location on a touch screen 412 cannot be simply evaluated digitally like the actuation of a mechanical key, for example, the processing unit 410 is configured to take into account a certain tolerance range when comparing the actual input to the desired input.

(36) Such a tolerance range is indicated in FIG. 4 by the dashed circle 422 around the symbol 416. In other words, any contact by the operator inside of the circle 422 marked on the touch screen 412 is evaluated by the processing unit 410 as corresponding to the desired input.

(37) FIG. 5 shows a fifth embodiment of a device for monitoring the attention of the operator; in this case, the processing unit 510 is coupled to a display unit 512 of any kind and to a gradually actuatable control 518 functioning as an input device.

(38) In order to monitor the attention of the operator, the processing unit 510 first randomly generates a desired value from a predetermined range, for example from 0 to 5. The processing unit 510 shows the operator this desired value on the display unit 512, prepared in a quantitative, graphic fashion in the form of a segmented bar graph 516.

(39) In FIG. 5, the bar graph 516 is shown in the left region of the display unit 512 and is composed of five segments 516, the lowest four of which are depicted as dark and the uppermost of which is depicted as light. Thus the randomly determined desired input is displayed to the operator as graphic information in the form of a bar graph 516.

(40) The operator can then perform an input within the predetermined time window by means of a gradually actuatable control 518, which, in the exemplary embodiment, is configured in the form of a pressure-detecting element that can be actuated by exerting an actuating force “F” on a key 519. The actuating element 518 differs from a conventional input key of the kind in the keyboard in FIG. 1 or FIG. 3 in that the actuating element 518 is able to detect the actuating force F exerted by the operator in a sufficiently gradual way, at least for the purposes required here, in the present case divided into at least 5 steps.

(41) The mechanically predetermined input range of the actuating element 518 from 0 (no actuation) to a maximum value of 5 (maximum force that can be exerted) is indicated in accordance with the segmentation of the graph bar 516, which indicates the desired input, on an identically configured graph bar 520 on the right side of the display unit 512.

(42) If the operator begins to press the pushbutton 519 of the control 518, then the pressure that is currently being exerted by the operator is reported back to the operator by means of the display bar 520. The operator therefore receives an optical feedback for the pressure he is exerting with the key 519.

(43) Within the predetermined time window for a positive feedback, the operator must adapt the pressure exerted on the key 519 so that the graph bar 516 representing the desired input and the one representing the actual input currently being exerted by the operator, which is represented by the graph bar 520, match.

(44) If within the predetermined time window, the processing unit determines that the actual input by the operator corresponds to the desired input, then this is once again evaluated as a positive indication for the attention of the operator.

(45) For better feedback to the operator, the processing unit 510 can be configured to optically change the graphic depiction of the bar 520 in a way that is clearly recognizable to the operator as soon as the exerted pressure on the key 519 corresponds to the actual input of the desired input. The operator must then maintain this state for a second short predetermined time period in order to trigger a positive input. This prevents an input by the operator from randomly corresponding to the desired input.

(46) As described above, the exemplary embodiment can be modified so that the display unit 512 is a touch screen and the control 518 is implemented by means of the touch-sensitive surface of the touch screen. In order to input a response, the operator then touches the display unit 512 functioning as an input element. The input is then carried out by controlling the bar 520 by executing a gesture such as a swiping or dragging on the surface of the display unit 512 with a finger. Otherwise, the operational procedure and the function are as described above in relation to FIG. 5.

(47) In the embodiments in FIGS. 2, 4, and 5, it is basically not possible for the operator to execute a digitally distinguishable correct or incorrect input. As explained above in connection with the embodiment in FIG. 4, this can fall within a tolerance range that can be defined in a sufficiently precise manner by means of experiments.

(48) In a way similar to the one described above in connection with the embodiment in FIG. 5, a modification can include an intensified feedback of current comparison results of the current actual input to the desired input.

(49) If the operator pays close attention to a feedback from the processing unit when making his input, then he can adjust his input within a predetermined input time window. For example, such an adjustment can be carried out by changing the contact point of the finger on a touch screen functioning as the input device (see FIG. 2 and FIG. 4 as well as the described possible modification to FIG. 5) and by changing the actuation of an actuating element (see FIG. 5).

(50) A correction possibility of this kind does not negatively affect the purpose of the monitoring device since the taking into account of this type of feedback to the operator can also be evaluated as an indicator for the attention of the operator.

(51) A feedback to the operator can take place via the display unit by means of an intuitively understandable color change, for example from red to green, possibly by way of yellow, in arbitrary steps that serve as an indication for the current deviation between the desired input and the actual input. Based on optical feedback information, the operator can then adjust the current actual input so that a “correct” input is achieved within the predetermined time window. This avoids unnecessary false alarms and exerts a motivating influence on the operator to correct his own actual input as needed.

(52) FIG. 6 shows a flow chart of an embodiment of a monitoring method implemented by means of one of the devices explained above in connection with FIGS. 1 through 5.

(53) In a step S1, for example by means of a random generator, the triggering of the monitoring method is initiated at irregular time intervals. This can take place, for example, by means of a random generator-controlled timer, which after going through a respective interrupt, triggers the execution of the monitoring method.

(54) As soon as the monitoring method has been triggered by the timer in step S1, the sequence proceeds to step S2 in which information is generated that defines a randomly determined desired input for the operator.

(55) Then the method proceeds to step S3 in which the randomly determined desired input is shown to the operator. Together with the display of the information to the operator, another predetermined timer is started, which defines the time window within which an input must be made by the operator.

(56) After step S3, the method proceeds to step S4 in which a possible input by the operator is detected in the input device.

(57) From step S4, the method proceeds to step S5 in which a check is performed as to whether the timer that has been started for the input time window has already expired or not. If the timer has already expired, then a negative evaluation of the operator's attention is issued and the method stops at this point and skips to step S10, which will be explained in greater detail below. If the timer has not yet expired, then the method proceeds from step S5 to step S6 in which a check is performed as to whether or not the operator has performed an input. If no input has been made by the operator, then the method returns from step S6 to step S4.

(58) If an input by the operator has been made, then the method proceeds from step S6 to step S7 in which the detected actual input by the operator, as the response to the desired input displayed, is compared to the desired input and a comparison result is generated.

(59) Then the method proceeds from step S7 to step S8, in which based on the desired input and the actual input, particularly based on the comparison result, a signal that indicates the attention of the operator is generated for further use.

(60) Then the method proceeds from step S8 to step S9, in which a check is performed as to whether or not the operator is paying attention. If the signal that indicates that the operator is paying attention shows that the operator is in fact paying attention, then the method returns from step S9 back to step S1 and is restarted from there after the random-generated triggering.

(61) If it is determined in step S9 that the operator is not paying attention, then the method proceeds from step S9 to step S10. In step S10, the signal that indicates that the operator is paying attention used as the basis for additional measures as follows.

(62) First, an alarm can be triggered, which is intended to draw the attention of the operator back to the system or machine that the operator is supposed to be monitoring. This makes it possible, after a defined window of time since the alarm was triggered, to restart the monitoring system, for example in order to determine whether the operator is now once again paying attention. In addition or alternatively, it is also possible to trigger an alarm at a higher level, for example at a position higher than the operator. It is then possible to take further steps from there as needed.

(63) Finally, the signal indicating the attention of the operator can also be used for direct measures to control the system or machine. For example, it is possible for the signal indicating the attention of the operator to be supplied to the system or machine via a signal input of a control unit, with the control unit bringing the system or machine into a predetermined safe state if it determines that the operator is not paying attention.

(64) The above-explained embodiments of the monitoring system are well-suited to systems or machines in which the attention of the operator is responsible among other things for the processing results of the machine or system. For example, the monitoring device and/or monitoring method can be used in an X-ray inspection system for nondestructive inspection of objects such as luggage items at an airport checkpoint, which is continuously supplied with luggage items, and an operator must examine transmission images of the luggage items. In this case, the operator's undivided attention is required since the inspection of the luggage items does not take place in a fully automated way, but instead, the inspection results largely also depend on the experience brought to bear by the operator. The operator's attention can be randomly, but regularly monitored with the above-described monitoring device and/or monitoring method.