JPS59212945A - Remote indication input device - Google Patents

Abstract

PURPOSE:To prevent the flicker for cursor display by giving A/D convertion to the scan light detection signal of an indication point, producing a coordinate signal from a pulse with which the integration value of the A/D output exceeds a prescribed level and averaging the time interval of the coordinate signal. CONSTITUTION:An optional point of the picture projected on a screen is indicated from a remote point, and the scan light of the indication point is detected by a photosensor 11. A signal S1 obtained by differentiating 12 and smoothing 13 a detection signal is sampled 14 by a timing signal S2, and this sampling output undergoes A/D conversion 15. The converted digital signals are counted 16 to obtain the integration value. An integration output signal S3 is compared with a level V1 set by a dip switch 17 through an AND gate 18. When the S3 exceeds the V1, the gate 18 delivers logic 1. The output of the gate 18 undergoes the matching of phase with vertical and horizontal scan synchronizing signals S4 and S6 respectively through PLL circuits 19 and 20. Thus the coordinate signal is produced for the indication point produced by a cursor. A counter 16 is reset with a signal S5 obtained by giving waveform shaping 21 to said coordinate signal. At the same time, the time interval of the coordinate signal is averaged by a fixed cycle forming circuit 22. Then the coordinate signal is delivered.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention specifies an arbitrary point on a screen on which an image (image on both sides of a CRT, etc.) is projected by scanning from a remote location, and creates an X, Y coordinate signal of the point. The present invention also relates to a remote instruction input device for inputting the created coordinate signal to a device for displaying a cursor on the indicated point.

Such a remote instruction input device is effective when applied to a video screen used in place of a blackboard at a conference table, etc., and a conventional example thereof is shown in FIG.

In FIG. 1, 1 is a video screen, 2 is a scanning light,
3 is a remote instruction input device, 4 is a processing device, 5 is a video signal, 6 is a CRT screen projection device, 7 is a cursor, and 8 is a scanning direction.0 Here, 081 screen projection device 6 is an input video signal 5
It has the function of converting the image into a scanning signal for image formation, and its principle is well known in devices such as televisions. However, in a television, an electron beam is irradiated onto a fluorescent surface inside a cathode ray tube to cause it to emit light and form an image, but the CRT screen projection device 6 irradiates scanning light onto the video screen 1, which is different from this point. Different from television.

The remote instruction input device 3 uses such a scanning light screen 1.
The processing device 4 corresponds to the input section of the device that detects the reflected light 2 by the screen and displays a cursor (position indication mark) 7 at the detected position on the screen, and uses the output from the remote instruction input device M3 as the timing. At this point, a video signal for cursor display is output to the projection device 6.

Such a circuit configuration of the remote instruction input device 30 is conventionally
As shown in the figure, it was composed of an optical sensor 31, a comparator 32, and an AND circuit 33 that matches the detection signal from the optical sensor 31 via the comparator 32 with horizontal and vertical scanning synchronization signals. That is, the optical sensor 31 detects the reflected light of the scanning light, compares it with a predefined voltage V by the comparator 32, and outputs a pulse when the voltage exceeds the voltage V. This pulse output is then used as the coordinate signal of the marker, but the distance between the video screen and the remote instruction manual device is not always constant and varies depending on the usage, so it is difficult to use under these conditions of use. Noise may be mixed into the detection signal that detects the scanning light due to changes in environmental conditions such as changes in the surrounding lighting or changes in the surrounding lighting.As a result, the power = crane display that specifies the coordinate position of the indicated point on the screen may flicker. There were other problems.

The present invention has been made to improve the problems of the prior art as described above, and therefore, an object of the present invention is to prevent the cursor display on the screen from flickering regardless of changes in usage conditions or environmental conditions. An object of the present invention is to provide a remote instruction input device that allows users to specify an arbitrary point on a screen on which an image is projected by scanning from a remote location, and to A remote instruction input device that creates a coordinate signal and inputs the created coordinate signal to a device for displaying a cursor on the indicated point, comprising: means for detecting scanning light at the indicated point; means for converting a detection signal from analog to digital (A/D); an integrating means for counting the converted digital signal and outputting an integral value of the detection signal; and when the integral value exceeds a set level. pulsing means for generating a pulse output; means for performing a phase comparison of the pulse output with horizontal and vertical scan synchronization signals of the image scanning to synchronize the synchronized signal and outputting a coordinate signal; It is characterized by comprising means for averaging the time intervals of the coordinate signals to make them at constant intervals.

Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 3 is a block diagram showing one embodiment of the present invention. In the figure, 11 is an optical sensor that detects scanning light, 12 is a differentiating circuit that removes the DC component of the detection signal from the optical sensor 11, 13 is a smoothing circuit that smoothes the output of the differentiating circuit, and 14
converts the smoothing circuit output S1 into a constant frequency timing signal S2
15 is an A/D converter for converting the sampled signal from analog to digital; 16 is the total amount (digital amount) of the magnitude of the sampling signal whose magnitude changes over time; 17 is a dip switch for setting a threshold, 18 is a dip switch 17
19 is an AND gate (digital comparator) for comparing the value set in 1 and the counter output value S3, and 19 is for comparing the phase of the vertical scanning synchronization signal S4 and the output of the AND gate 18 to achieve synchronization. PLL (7A locked loop) circuit, 20 is horizontal scanning synchronization signal S
6 and the output of the AND gate 18 for synchronization; 21 is a waveform shaping circuit for shaping the pulse waveform of the output of the PLL circuit; This is a constant periodization circuit that averages the period of pulse signals obtained sequentially to a constant period. - FIG. 4 is a time chart of various signals in the circuit of FIG. 3.

FIG. 5(a) is an explanatory diagram showing the range M in which the optical sensor 11 detects scanning light on the screen 1, and FIG. 5(b) is a waveform diagram showing the waveform of the detection signal output by the optical sensor 11. be.

The operation of one embodiment of the present invention will be described with reference to FIGS. 3 to 5.

As shown in 5th [J(a), the scanning light on the video screen 1 is first scanned in the horizontal direction with the upper left corner as a reference, and after reaching the right edge, it moves downward by one scanning pitch, and then moves to the left edge. The image is displayed by repeating the process of scanning in the right direction from the coordinates. At this time, the signal detected by the optical sensor 11 is a signal obtained by scanning the detection range M indicated by diagonal lines in FIG. 5(a), and its waveform is as shown in FIG. It is detected as a waveform as shown.

Such a detection signal is affected by the influence of ambient light and the light sensor 1.
It contains noise due to the light receiving conditions of No. 1, etc., and it is necessary to take measures to improve the S/N ratio.

In Fig. 3, the signal rate detected by the optical sensor 11 has a low S/N ratio due to the four signals described above, so first, the differential circuit 12 cuts out the DC component, thereby removing the influence of surrounding light. . Next, the output signal of the differentiating circuit 12 is integrated in order to remove irregular harmonic components included in the detection signal and obtain a stable detection signal. Here, the output signal of the differentiating circuit 12 is simply integrated. Then, since the positive and negative values are canceled out, they are smoothed through a smoothing circuit (bridge) as shown in 13. The integration circuit for integrating this smoothed output can be easily realized using an analog circuit, but if it is realized in a form that also has an A/D conversion function, for example, the circuit configuration shown by the broken line in Fig. 3 is required. Becomes an engineer.

That is, the integrating circuit I includes a sampling circuit 14 that samples the output S1 of the smoothing circuit 13 using a timing signal S2 having a constant period, and an A/D
It consists of an A/D converter 15 for conversion, and a counter 16 for counting the converted digital amount and outputting an integral value S3.

Note that the signal S1. S2. S3 is a signal as shown in the time chart of FIG.

Returning to FIG. 3, the integral value output signal S3 is output from the AND gate 18.
, the signal is compared with the V rubel set by the dip switch 17, and if it exceeds the V rubel, the logic "
1” level signal is output.

Here, the magnitude of the level V1 may be determined in accordance with the maximum peak of the output signal S1 of the smoothing circuit 13, for example.
Changes in the peak caused by changes in the distance between the screen and the optical sensor can be dealt with by manually adjusting the setting level of the dip switch 7.

The output signal of the AND gate 18 is phase-aligned with the vertical scan synchronization signal S4 and the horizontal scan synchronization signal S6 in PLL circuits 19 and 20.
By using the phase-aligned signals from the LL circuits 19 and 20, it is possible to obtain the coordinate signal of the designated point where the cursor on the screen should be generated in synchronization with the scanning synchronization signal. This can improve the flickering of the cursor that occurs on the screen when the cursor is out of sync.

Note that the outputs of the PLL circuits 19 and 20 are shaped into a waveform having a prescribed pulse width by a waveform shaping circuit 21 such as a monostable multivibrator. The output signal that has been subjected to such waveform shaping processing is synchronized by comparing the phase of the vertical scanning synchronization signal S4 and the output signal of the AND gate 18, and has a waveform like 85 in FIG. 4. becomes. Note that this output signal S5 is also used to reset the counter 16.

Next, the constant periodization circuit 22 is used to regularize the waveform shaped output S5 when it is no longer generated at a constant period due to fluctuations in the integral signal S3.

When the integral signal S3 changes from ■ to ■ as shown in FIG. 6(a) according to the waveform of the detection signal from the optical sensor 1, the waveform changes based on the relationship already explained! The signal of the shaped output S5 changes from ■ to ■, resulting in a change in . This results in variations in the cursor position as shown in FIG. 6). Here, Δt
In order to reduce the effect of What is necessary is to obtain S5. It goes without saying that the periodicization circuit used for this purpose can be easily constructed by using a shift register or the like.

As described above, the present invention has the advantage that it is possible to provide a highly accurate remote instruction input device in which the cursor display on the screen does not flicker regardless of changes in usage conditions or surrounding environment.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a conventional example of a remote instruction input device;
The figure is a circuit diagram showing the circuit configuration of a conventional remote instruction input device.
FIG. 3 is a block diagram showing one embodiment of the present invention, FIG. 4 is a time chart of various signals in the circuit of FIG. 3, and FIG.
Figure (a) is an explanatory diagram showing the range M in which the optical sensor detects scanning light on the screen, Figure 5 (b) is a waveform diagram of the detection signal output by the optical sensor, and Figure 6 (a) is the detection signal. FIG. 6(b) is a time chart showing changes in the coordinate signal that occur when the integral signal fluctuates depending on the waveform of FIG. Description of symbols 1...Video screen, 2...Scanning light, 3...Remote instruction input device, 4...
Processing device, 5...Video signal, 6...
CRT screen projection device, 7...Cursor, 8...
...Scanning direction, 11... Optical sensor, 12.
... Differential circuit, 13 ... Smoothing circuit, 14
・・・・・・Sampling circuit, 15・・・・・・A/
D converter, 16... Counter, 17...
・Dip switch, 18...AND game), 1
9, 20... PLL circuit, 21... Waveform shaping circuit, 22... Fixed periodization circuit, 31...
... Light sensor, 32 ... Comparator, 3
3...AND circuit agent Akio Namiki Patent attorney Agent Kiyoshi Matsuzaki Figure 1 Figure 2 Figure 74-IIa Figure 4 Figure 8.

Claims (1)

[Claims] 1) Indicating an arbitrary point on the screen on which an image is projected by scanning from a remote location, creating a coordinate signal of the point, and displaying the created coordinate signal as a cursor at the designated point. A remote instruction input device input to the device, which includes a means for detecting the scanning light at the instruction point, and a detection signal from the means is converted into analog/digital (A/D).
D') converting means, integrating means for counting the converted digital signal and outputting an integral value of the detection signal, and pulsing means for generating a pulse output when the integral value exceeds a set level. , a means for synchronizing the pulse output with a horizontal and vertical scanning synchronization signal of the image scanning to output a coordinate signal, and averaging a time interval of the coordinate signal outputted in time series. 1. A remote instruction input device comprising: a means for setting a fixed interval at regular intervals.