3rd, coherent signal gain
In order to gain the quality higher coherent signal, we use the signal sensor installment which chart 3 shows.

This equipment is composed by two groups optics characteristics quite same not less than optical system, after the identical signal passes through two groups of optical systems output signal theoretically to be supposed to be quite same not less than, optical system sensitive wave band for 红外�? Two groups of optical systems optical axis is distanced 25mm, precisely processes two groups of optical systems and fixes in the same place, forms the correlation to measure the fast meter the infrared optical pickoff. When survey, aims at this sensor the movement the hot rolling steel products, then two groups optical systems gather to the steel products identical physical location the signal only differs a time delay, is the correlation very good two group signals. This detention namely for the transit time tau 0, then obtains the hot rolling steel products by (2) the formula the velocity of movement:

Obviously, the precision measuring transit time tau 0 values are the realization accurate survey hot rolling steel products velocity of movement keys.

4th, transit time tau 0 on-line surveys and computation
May know by the correlation function nature, two quite same not less than signals correlations are biggest, comes two groups signals from the infrared sensor only to differ a time delay. And makes after some direction data shifting the correlation operation, recording shifting integer, when shifts same to two groups of data corresponding points, the correlation is biggest. Through this greatest correlative value correspondence shifting integer, then extracts the transit time. When, tries to the signal to carry on the shifting comparison, discovers its correlative value greatest the motion gap to become this system information processing the key. Therefore, we use the signal processing method which chart 4 shows to seek the transit time. On, the downriver signal after the amplifier, carries on two values processing, and separately saves the result to the memory 1 and the memory in 2, then continuously changes the time delay address. The time delay address every time changes a time, after and upstream data shifting corresponds the downriver data the data to do time different or the non- operation, and with the counter accumulation operation result, one by one shifting discovers the counter the maximum value, again extracts the sampling through the shifting integer to be separated N. Supposes sampling the clock cycle is T, then the transit time is:

5th, measures the fast meter the present situation analysis and the improvement method
According to the above principle, we have developed measured the fast meter the prototype, the actual use indicated: Oxidizes the iron sheet to the hot rolling material on to distribute big and the sparse survey object, measured the fast meter survey accurate also is stable, can satisfy the survey request; But oxidizes the iron sheet to the hot rolling material on to distribute small and the dense survey object, the data output insufficiently is stable, must further improve.

In view of measured the fast meter exists the question, we take the following measure to measure the fast meter has made the improvement.
(1) enhances, the downriver signal uniformity. It is well known, signal more similar, its relevance is bigger. Therefore, must try to cause, the downriver signal to be as far as possible similar. Concrete procedure as follows:
(1) causes the infrared sensor two groups optical system to be consistent as far as possible, this is the correlation measures the fast foundation. Causes to measure on the object, the downriver two group similar signal after the optical system, the output signal were still similar, enhanced the infrared sensor output signal the relevance.

(2) causes the infrared sensor two groups optical systems the slit size to be equal as far as possible. The experiment indicated, to identical survey object, adjustment optical system slit, when two groups sizes equal, related result good, determines the hot rolling material speed accurate and is stable.

(3) causes two groups signals processes enlargement electric circuit performance which the infrared sensor outputs to be consistent as far as possible. After this may cause two groups relevant very good signals enlargement, its relevance very was still good. This is after guaranteed two groups coherent signals digitization still maintained the consistent important link.

(2) enhances the signal the quality. Provides the high grade signal, the computer can process the correct result. Concrete procedure as follows:
(1) adds on the infrared light filter in front of the infrared sensor. Designs to us outside measured the fast meter, the electric eye becomes lucky the wave length to be most sensitive, but certainly is not had not responded to other wave lengths light. Thus after joins the infrared light filter, but effectively removes in the signal 杂散 the signal, greatly enhances the input signal the quality.

(2) selects two quite same not less than fiber optic transmissions signal, and in satisfies the transmission request in the situation, causes it to be as far as possible short. Like this does not send to in the fiber optic transmission process the signal distortion, but causes the relevance to drop.

Before (3) pair of computer gathering signal carries on the pretreatment. The optical signal the signal which outputs after the infrared sensor passes on after the optical fiber to when processes the electric circuit, after first passes through enlargement reshaping processing, the computer carries on gathering again to it, enhances the gathering signal the accuracy.

(3) suppresses the average effect. Measured the fast meter to oxidizes the iron sheet to distribute small and is dense was measured the object survey reason mainly is because the average effect causes. Therefore, must overcome the average effect as far as possible to the survey the influence. In order to effectively suppresses the average effect, may reduce the infrared sensor optical system the slit. The practice proved like this can effectively suppress the average effect, but, the slit reduces follows the signal energy reducing, therefore, when reduces the slit must consider the increase signal the energy. Increase signal energy concrete procedure as follows:
(1) enhances the amplifier the enlargement factor, increases inputs is measured to the computer in the signal the energy.

(2) reduces the infrared sensor and the survey object distance, enhances the input signal the energy.

(3) reduces the signal the transmission link. Reduces the optical fiber the transmitting range, in the possible situation, to remove the fiber optic transmission link, directly installs the pre-amplification above the infrared sensor, like this needs to add on a water-cooling system, cools the work system.
At present, the correlation measured the fast meter obtained the application in the horse steel hot rolling steel products scene. According to the method which in the article states to measured the fast meter has made the improvement, in the actual use the proof is extremely effective.