CN102005167A

CN102005167A - Verification and sampling method for LED (light-emitting diode) screen taximeter

Info

Publication number: CN102005167A
Application number: CN 201010502261
Authority: CN
Inventors: 黄锋
Original assignee: Guangzhou City Institute Of Measurement Detection Technology
Current assignee: GUANGZHOU INSTITUTE OF MEASURING AND TESTING TECHNOLOGY
Priority date: 2010-09-30
Filing date: 2010-09-30
Publication date: 2011-04-06
Anticipated expiration: 2030-09-30
Also published as: CN102005167B

Abstract

The invention discloses a verification and sampling method for an LED (light-emitting diode) screen taximeter, and the method comprises the following steps: A) using a photosensor element to sense brightness maximum value M of reference number strokes on money amount changing bits of an LED screen of the taximeter, and multiplying the brightness maximum value M by brightness coefficient k as a brightness reference signal, that is L equals to kM; B) obtaining a scanning synchronizing signal of the reference number strokes on the money amount changing bits of the LED screen of the taximeter; C) using the photosensor element to sense brightness T of characteristic number strokes in seven sections of LED number strokes according to the scanning synchronizing signal when scanning the number strokes of the LED screen; and D) comparing the brightness T of the characteristic number strokes in the seven sections of the LED number strokes with the brightness reference signal L, obtaining an on-state comparison signal when the T is more than or equivalent to the L, and obtaining an off-state comparison signal when the T is less than the L. The verification and sampling method can improve the verification precision and lead the operation to be simpler.

Description

The taxi LED screen fee register calibrating method of sampling

Technical field

The invention belongs to the Measuring and testing field, be specifically related to a kind of taxi LED screen fee register calibrating method of sampling.

Background technology

Taxi originates from New York in 1907, and the very fast whole world in fashion, and simultaneously similar, taxi has also imported China into.According to Chinese taxi and automobile leasing association statistics, to 2009, several more than 100 ten thousand of the existing taxi on the regular payroll of China, the practitioner nearly 2,000,000, taxi be known as " city business card ", along with improving constantly of living standards of the people, it has been usual thing that citizen " beat ", and the taxi behavior had become the industry closely bound up with citizen's daily life already.

What taxi operation was the most basic is the charge of having the records of distance by the log, taxi driving range metering charge by be mounted in the fee register of having the records of distance by the log on the taxi, in order to guarantee trade both sides' equitable interest, the accuracy of monitoring taxi driving range metering valuation is the people's livelihood item that countries in the world government is all managing.In China, be responsible for supervising the fairness that taxi is had the records of distance by the log and valuated by quality supervision departments at different levels, according to JJG517 " taximeter " national metrological verification regulations measurement verification is carried out in taxi driving range metering valuation by country's measurement verification technical bodies at different levels, guaranteed the taxi driving range metering fee register accurately and reliably.

The mode of taximeter being carried out measurement verification is: the taxi vehicle wheel frame that fee register will be installed is on normal drum, the girth of this normal drum is measured exactly, the revolution speed measuring device is installed on the cylinder can measures the revolution of cylinder (this normal drum and corresponding measurement mechanism general designation taximeter use error calibrating installation) exactly, thereby rotating drive taxi wheel with the motor head roll rotates synchronously, in rotating process, taximeter use error calibrating installation is by measuring the revolution n that cylinder rotates, because cylinder girth C is known, therefore cylinder rotation distance is L=nC, fee register on the taxi that rotates has a measured value A simultaneously synchronously, just know the accuracy of fee register measurement by L relatively and the difference of A, the calibration method principle of Here it is taximeter.

In the verification process of fee register, because the final function of fee register is charge, thus the national metrological verification regulations regulation adopt the measured value L that judges fee register toll amount saltus step taximeter use error calibrating installation during moment and fee register toll amount saltus step moment the error of the distance value B that should represent.Need to obtain the measured value L of taximeter use error calibrating installation when therefore examining and determine at fee register toll amount saltus step instantaneous sampling.Present measurement verification technical body at different levels carries out the visual method of all sampling when fee register is examined and determine, and adopts the amount of money screen of Direct observation fee register, when observing fee register toll amount generation saltus step, presses " sampling " key of calibrating installation immediately; Or, the amount of money screen image of fee register is presented on the display screen of calibrating operation room same visual the sampling with the means of shooting; The speed of calibrating installation is 60km/h during calibrating, therefore to the rate request of amount of money saltus step instantaneous sampling action just than higher, also bring 1.7 meters action error even incur loss through delay 0.1s, cause detecting inconvenience, also have influence on the accuracy of detection.

Summary of the invention

The objective of the invention is to overcome the defective of prior art, a kind of taxi LED screen fee register calibrating method of sampling is provided, the present invention has improved the accuracy of calibrating, and operation is simpler.

Its technical scheme is as follows:

A kind of taxi LED screen fee register calibrating method of sampling, this method comprises the steps:

A, change the brightness maximal value M of benchmark stroke in the benchmark stroke on the figure place, and multiply by the reference signal L of luminance factor k as " bright ", i.e. L=kM with this brightness maximal value M by the light activated element sensing fee register LED screen amount of money; B, obtain the scan-synchronized signal that the fee register LED screen amount of money changes the benchmark stroke on the figure place; C, according to the scan-synchronized signal, when the scanning of LED screen stroke, with the brightness T of feature stroke in seven sections LED strokes of light activated element sensing; D, the brightness T of feature stroke in seven sections LED strokes and " bright " reference signal L are made comparisons,, obtain the state comparison signal of " bright ",, obtain the state comparison signal of " going out " as T during less than L as T during more than or equal to L.

The technical scheme of the further refinement of aforementioned techniques scheme can be:

In the step A, described luminance factor k gets 0.5 to 0.7 (as getting 0.667).

Described tagged word divides two strokes in the lower left corner and bottom of seven sections LED strokes into.

The right that described character datum divides seven sections LED strokes into is two strokes up and down.

In the step B, the reference signal L of " bright " in the A step is kept, obtain logic level signal after treatment; Logic level signal and square-wave signal are carried out the monopulse digital processing, and resulting periodic pulse signal is described scan-synchronized signal.

After described D step, also has a step e: with the state comparison signal input trigger of " bright " in the described D step or " going out ", and adopt the control signal of described scan-synchronized signal as trigger, in described scan-synchronized in the signal period, obtain the state comparison signal of LED stroke " bright " or " going out ", and it is maintained to the next scan-synchronized cycle, and and by the logic level signal of trigger output " bright " or " going out ", i.e. stroke status signal in real time.

The selection that aforementioned " benchmark stroke " reaches " feature stroke " is not what fix, but is provided with according to the actual needs, adjusts.

In sum, advantage of the present invention is:

1, by light activated element seven sections LED strokes that fee register LED shields is carried out sensing, improved the accuracy of calibrating, and operation is simpler;

No matter 2 is to show any numeral, the right of seven sections LED strokes is two strokes up and down, it is bright having a stroke at least, two strokes are as the benchmark stroke about selecting the right for use, consider to exist between stroke brightness irregularities simultaneously, M multiply by the reference signal of luminance factor k as " bright " with this brightness maximal value, improves the reliability and the accuracy that detect;

3, when fee register LED screen is jumping valency step value by 1, two strokes of the lower left corner and bottom can be sent out and change in seven sections LED strokes, so adopt these two strokes as the feature stroke, can shield the jumping valency by sensing fee register LED, adopt the mode of feature stroke, can reduce the quantity of light activated element, and reduce cost with this;

4, fee register LED screen amount of money screen shows it is the mode that sampled scan shows, generally is that per 25 milliseconds of scannings show that once the LED charactron of each figure place shows about 1 millisecond in order respectively during scanning; The present invention obtains the scan-synchronized signal of seven sections LED stroke scannings, and detects in 1 millisecond of time that the LED charactron shows, both carry out synchronously, has improved the accuracy and the reliability that detect;

5, the amplitude of LED stroke " bright " reference signal is uncertain, by it is carried out data processing, obtains the logic level signal of amplitude stability, the processing of more convenient down-stream and application.

Description of drawings

Fig. 1 is the described seven sections LED stroke synoptic diagram of the embodiment of the invention;

Fig. 2 is seven sections LED stroke synoptic diagram of 0 to 9;

Fig. 3 is that the LED charactron shows stroke luminance signal synoptic diagram;

Fig. 4 is that LED charactron scan synchronizing signal is handled synoptic diagram;

Fig. 5 is a LED charactron scan synchronizing signal sequential chart;

Fig. 6 is that feature stroke status signal produces sequential chart.

Embodiment

Below in conjunction with accompanying drawing embodiments of the invention are elaborated:

A, change the brightness maximal value M of benchmark stroke in the benchmark stroke on the figure place (the right that character datum divides seven sections LED strokes into is two strokes up and down) by the light activated element sensing fee register LED screen amount of money, and multiply by the reference signal L of luminance factor k as " bright " with this brightness maximal value M, be L=kM (in the present embodiment, luminance factor k gets 0.667);

B, obtain the scan-synchronized signal that the fee register LED screen amount of money changes the benchmark stroke on the figure place, particularly: the reference signal L of " bright " in the A step is kept, and make signal peak after the maintenance less than the amplitude of original maximum brightness value M; Signal and original maximum brightness value M after keeping are compared, obtain and the identical logic level signal of original high-high brightness signal shape; Logic level signal and square-wave signal are carried out the monopulse digital processing, and resulting periodic pulse signal is described scan-synchronized signal;

C, according to the scan-synchronized signal, when the scanning of LED screen stroke, with the brightness T of feature stroke in seven sections LED strokes of light activated element sensing (tagged word divides two strokes in the lower left corner and bottom of seven sections LED strokes into);

D, the brightness T of feature stroke in seven sections LED strokes and " bright " reference signal L are made comparisons,, obtain the state comparison signal of " bright ",, obtain the state comparison signal of " going out " as T during less than L as T during more than or equal to L.

E: with the state comparison signal input trigger of " bright " in the described D step or " going out ", and adopt the control signal of described scan-synchronized signal as trigger, in described scan-synchronized in the signal period, obtain the state comparison signal of LED stroke " bright " or " going out ", and it is maintained to the next scan-synchronized cycle, and by the logic level signal of trigger output " bright " or " going out ", i.e. stroke status signal in real time.

Elaborate below in conjunction with accompanying drawing:

A numeral constitutes (as shown in Figure 1) by 7 sections strokes in theory, but the purpose of present embodiment is the variation of discriminating digit, therefore not necessarily needs the numeral of distinguishing concrete; When numeral from 0 to 9 circular order changed, the state of its e section and the combination of d section must change (as shown in Figure 2), so as the feature stroke, when showing 0 to 9, the situation of change of characteristic of correspondence stroke is as shown in the table with these two strokes for present embodiment:

0

1

2

3

4

5

6

7

8

9

The e stroke

Bright

Go out

Bright

Go out

Bright

Go out

Bright

Go out

The d stroke

Bright

Go out

Bright

Go out

Bright

Go out

Bright

Thereby present embodiment is the variation moment that changes the acquisition numeral by the light on and off of stroke, thereby realizes the sampling function of fee register calibrating; And bright, the state of going out of stroke are by the size of stroke bright pulse signal amplitude is differentiated, and the LED pipe stroke brightness of different fee register production factory may be different; On the other hand, seven sections LED strokes the right " Shu " up and down two strokes (b, c) must to have stroke at least be bright, so select for use these two strokes as the benchmark stroke, benchmark stroke brightness maximal value M multiply by the reference signal of luminance factor k as " bright ".

, the LED charactron shows that in non-section sweep time (being generally 25 milliseconds), no matter be that the stroke or the stroke of " secretly " of " bright " all is dark, its luminance signal is identical because being scanning; Only in section sweep time (being generally 1 millisecond), the stroke of " bright " is only bright (as shown in Figure 3).So, need a LED pipe scan-synchronized signal, only judge the stroke brightness in the synchronizing signal time, in other words, promptly when LED stroke " bright " reference signal scanning display time interval, measure the brightness of stroke more to be measured, and do not scanning display time interval, then keep the state of stroke to be measured in LED stroke " bright " reference signal.But because the amplitude of LED stroke " bright " reference signal is uncertain, be difficult in circuit, use, therefore the uncertain LED stroke of amplitude " bright " reference signal to be done the signal amplitude processing and be transformed to logic level signal (as Fig. 4, shown in Figure 5), again the signal input trigger is carried out data processing, obtain stroke real-time status signal (as shown in Figure 6).

Be specific embodiments of the invention only below, do not limit protection scope of the present invention with this; Any replacement and the improvement done on the basis of not violating the present invention's design all belong to protection scope of the present invention.

Claims

1. a taxi LED screen fee register calibrating method of sampling is characterized in that this method comprises the steps:

A, change the brightness maximal value M of benchmark stroke in the benchmark stroke on the figure place, and multiply by the reference signal L of luminance factor k as " bright ", i.e. L=kM with this brightness maximal value M by the light activated element sensing fee register LED screen amount of money;

B, obtain the scan-synchronized signal that the fee register LED screen amount of money changes the benchmark stroke on the figure place;

C, according to the scan-synchronized signal, when the scanning of LED screen stroke, with the brightness T of feature stroke in seven sections LED strokes of light activated element sensing;

2. taxi LED screen fee register is examined and determine the method for sampling according to claim 1, it is characterized in that in the step A, described luminance factor k gets 0.5 to 0.7.

3. taxi LED screen fee register is examined and determine the method for sampling according to claim 1, it is characterized in that described tagged word divides two strokes in the lower left corner and bottom of seven sections LED strokes into.

4. the taxi LED screen fee register calibrating method of sampling according to claim 1 is characterized in that, the right that described character datum divides seven sections LED strokes into is two strokes up and down.

5. as the taxi LED screen fee register calibrating method of sampling as described in each in the claim 1 to 4, it is characterized in that, in the step B, the reference signal L of " bright " in the A step is kept, obtain logic level signal after treatment; Logic level signal and square-wave signal are carried out the monopulse digital processing, and resulting periodic pulse signal is described scan-synchronized signal.

6. as the taxi LED screen fee register calibrating method of sampling as described in the claim 5, it is characterized in that, after described D step, also has a step e: with the state comparison signal input trigger of " bright " in the described D step or " going out ", and adopt the control signal of described scan-synchronized signal as trigger, in described scan-synchronized in the signal period, obtain the state comparison signal of LED stroke " bright " or " going out ", and it is maintained to the next scan-synchronized cycle, and by the logic level signal of trigger output " bright " or " going out ".