KR20130036322A - Measurement device using ccd camera, and method for shortening response time thereof - Google Patents

Abstract

As a shortening method of the response time of the measuring apparatus 100 which controls the exposure time of a CCD camera within the time of a preset control period, a CCD camera is a camera which can simultaneously acquire two or more filter outputs of different transmittance | permeability. The transmittance is ε _ND1 > ε _ND2 >. ε _NDi > ε _{NDi + 1} >. The saturation value of the measurement range of the camera output of the first filter having a higher transmittance ε _NDi for detecting the minimum value of the input light amount as> ε _{NDi + n} and the camera of the second filter having the lower transmittance ε _{NDi + 1} When the minimum value of the measurement range of output is the transmittance | permeability which wraps, and when the camera output of a 1st filter is saturated, from a camera output of a 2nd filter, or from the ratio of transmittance epsilon _NDi and transmittance epsilon _{NDi +} 1, The correction gain of the exposure time converted into the camera output of the filter is obtained, the input light amount is detected in the previous control period, and the exposure time of the camera of the first filter is updated in the next control period.

Description

Measuring device using a CCD camera, and a method for shortening the response time {MEASUREMENT DEVICE USING CCD CAMERA, AND METHOD FOR SHORTENING RESPONSE TIME THEREOF}

The present invention relates to a measuring apparatus using a CCD camera that irradiates a laser beam to an object to be measured, detects a positional change of reflected light from the object to be measured by a CCD camera, and measures the shape of the object to be measured.

As a measuring apparatus for the shape of various materials such as steel sheets, there is a measuring apparatus using a CCD camera that irradiates a laser beam to the steel sheet, detects a change in the position of the reflected light with a CCD camera, and measures the shape of the object to be measured, etc. (Example See, for example, Patent Document 1.).

Generally, the measuring apparatus used in manufacturing processes, such as a steel plate, measures from the front-end | tip part to the tail end (rear end part) of the steel plate conveyed, and yields a product by the quantity of a measured quantity. Therefore, the position of the tip portion to be measured is important.

For example, in the case of the thickness measuring apparatus using the distance measuring apparatus disclosed in patent document 1, it is an important function that it can measure from which position of the steel plate front end part the thickness which satisfy | fills a product standard. The response time from the tip to the position where the correct measurement is possible is also called the tip response.

However, in the case of the distance measuring device that receives the reflected light of the laser beam from the steel sheet and measures the distance, the state of the reflected light varies in reflection characteristics at the tip of the steel sheet, so that the output of the CCD camera is saturated, or There is a problem that the tip response is not stabilized because the noise level is lowered or lowered.

In the conventional optical distance measuring device, a control circuit in which the CCD camera output is made constant is provided, and the detection signal is stabilized. In the case of a distance measuring device having a line scan type CCD camera, the exposure time of the CCD camera (also referred to as the accumulation time or the shutter time in the case of CCD), so that the output of the CCD camera is stabilized within a certain range, The AGC (Automatic Gain Control) function to control the signal level by controlling the time.

In general, the AGC response of the line scan type CCD camera requires three times as long as a control period (also referred to as a measurement period or a calculation period) of a preset measurement device, as shown in FIG. . That is, in the preset control period, the change of the exposure time includes the first control period S _P1 for detecting and storing the CCD camera signal, the second control period S _P2 for reading the stored CCD camera data, and the read camera. Three times the control period S _P of the third control period S _P3 for determining the exposure time for determining the level of the CCD camera signal preset from the data is required. When it is possible to terminate the reading and calculation within the same control period, the control cycle can be doubled.

The exposure time is updated in units of control cycles in a time range of a preset control cycle to control the CCD camera output. However, when the CCD camera signal is set to an exposure time that can be measured at 10% of the saturation exposure amount of the CCD camera, the output of the CCD camera for this 10% is saturated by 10 times or more of the input light amount. When there is more than twice the amount of input light, the exposure time cannot be controlled.

For example, in the prediction, since the received light amount at the tip of the steel sheet needs at least about 200 times the minimum input light amount from the change in reflectance and its diffusion characteristic, the saturated state cannot be avoided.

Therefore, a method of setting an optical filter for reducing the amount of received light to a CCD camera, detecting the amount of received light and changing the exposure time is conceivable. However, in this case, there is a problem that the mechanical setting time of the optical filter is required, and the tip response is remarkably slowed down.

Patent No. 3966804 (Fig. 1, page 1)

As described above, in the case of the measuring device with the line scan type CCD camera, when there is an excessive amount of input light exceeding the saturated exposure amount of the CCD camera in the setting of the exposure time in a preset control period, the input Means for detecting the degree of intensity of the light amount are required, and control for updating the exposure time in the shortest time cannot be performed. Therefore, there exists a problem that the response time of a measuring apparatus becomes slow.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and in a CCD camera which controls the exposure time within a time of a predetermined control period, the shortest time is measured for an excessive amount of input light exceeding the saturated exposure amount of the CCD camera. It is an object of the present invention to provide a measuring device capable of obtaining a possible CCD camera signal, and a method for shortening the response time thereof.

In order to achieve the above object, the measuring device using the CCD camera of the present embodiment includes a light source unit for irradiating a laser beam to the surface of the object to be measured, and a line scan type CCD camera for detecting reflected light of the laser beam. A measuring device having a detection unit and a control unit for obtaining a measurement amount such as the shape of the measurement object from the output of the CCD camera, wherein the control unit generates a control period signal of the measurement amount obtained by the control unit, and generates each unit in the control unit. And a control circuit for inputting and transmitting the camera output signal of the CCD camera, a memory for storing the camera output signal transmitted from the control circuit, camera data of the stored camera output signal, and a preset camera output. Compare the set values of the levels, so that the camera output is constant. And an AGC circuit section for controlling the exposure time set within the time of the control period of d, and a calculation section for obtaining the measurement amount from the CCD data controlled by the AGC circuit section, wherein the CCD camera includes a plurality of line scan types. The ND filter comprises a first ND filter _having a transmittance ε _ND0 , a second ND filter having a transmittance ε _ND1 , and a third ND filter having a transmittance ε _ND2 . The magnitude of the transmittance is ε _ND0 > ε _ND1 > ε _ND2 , the saturation value of the camera output of the first ND filter and the lower limit value of the measurement range of the second ND filter, and the second ND. The saturation value of the filter and the lower limit value of the measurement range of the third ND filter are respectively set to transmittances of lapping, and the AGC circuit portion determines whether or not the camera output of the first ND filter is saturated. D ₎ The ratio between the set value of the output level and the output D ₀ of the first ND filter is obtained to obtain the first correction gain α1, the exposure time corresponding to the obtained first correction gain is obtained, and the exposure time before the correction is obtained. When updating with time, when the camera output of the first ND filter is saturated, and the saturation and unsaturated of the camera output of the second ND filter is determined, and the camera output of the second ND filter is unsaturated, For the second ND filter 2 camera output D ₁ , a second correction gain is obtained from the ratio of the set value and the output D ₁ of the first ND filter, and an exposure time corresponding to the obtained second correction gain is obtained. And if the exposure time before correction is updated to the exposure time, and the camera output of the second ND filter is saturated, the set value and the first ND filter of the camera output D ₂ of the third ND filter. Print Obtain a third correction gain from the ratio of?, And obtain an exposure time corresponding to the obtained third correction gain, update the exposure time before correction to the exposure time, and output the camera output of the first ND filter of the CCD camera. If there is an excessive amount of input light to saturate, the correction gain for the first ND filter is obtained from the camera output of the second ND filter or the camera output of the third ND filter, and the change of one exposure time is performed. It is characterized by that it is possible to measure.

MEANS TO SOLVE THE PROBLEM The measuring apparatus using the CCD camera of this embodiment is equipped with the light source part which irradiates a laser beam to the surface of a to-be-measured object, and the line scan type CCD camera which detects the position of the reflected light of the said laser beam. A measuring device having a detecting unit for determining a measuring amount such as a shape of a measuring object and the like from an output of the CCD camera, wherein the control unit generates a control period signal of the measuring amount obtained by the controlling unit, A control circuit for inputting and transmitting a camera output signal of the CCD camera, a memory for storing the camera output signal transmitted from the control circuit, a camera data of the stored camera output signal, and a preset camera Compare the setting value of the output level so that the corresponding camera output is constant An AGC circuit section for controlling the exposure time set within the time period of the control cycle of the CCD camera, and an arithmetic section for obtaining a measurement amount from the CCD camera controlled by the AGC circuit section, wherein the CCD camera has a line scan type RGB. A color camera having a filter, wherein the peak value of the wavelength of the laser beam selects a wavelength at which the transmittance? R of the R filter is 90% or more, and the AGC circuit portion is saturated with the camera output of the R filter. In the case of desaturation, the ratio of the camera output set value and the output D ₀ of the R filter is determined to be the first correction gain, and the exposure time corresponding to the obtained first correction gain is obtained to determine the When the exposure time is updated to the exposure time and the camera output of the R filter is saturated, the saturation and unsaturated of the camera output of the B filter are further determined. When the camera output of the B filter is unsaturated and is equal to or lower than the lower limit of the measurement range, a value obtained by multiplying the set value by the ratio of the transmittances of the B filter and the R filter is obtained by calculating the value of the camera output of the B filter. 2 the correction gain is obtained, and the exposure time corresponding to the obtained second correction gain is obtained, and the exposure time before the correction is updated to the exposure time, and when unsaturated and in the measurement range, converted to the camera output of the R filter. In one case, the third correction gain set as the output level of the measurement range is selected, the exposure time corresponding to the third correction gain is obtained, the exposure time before correction is updated by the exposure time, and the camera output of the B filter. If is saturated, select the fourth preset correction gain which becomes the measurement area when converted to the camera output of the R filter, and When the corresponding exposure time is obtained and the exposure time before correction is updated to the exposure time, and the input light amount of the CCD camera is an excessive input that saturates the camera output of the R filter, the camera output of the B filter is And the first to fourth correction gains are obtained from the ratio of the transmittances of the B filter and the R filter, and an exposure time for which the camera output of the R filter is a preset set value is obtained.

In order to achieve the above object, the shortening method of the response time of the measuring apparatus using the CCD camera of this embodiment is based on the response time of the measuring apparatus 100 which controls the exposure time of the CCD camera within the time of a preset control period. As a shortening method, the CCD camera is a camera capable of simultaneously obtaining two or more filter outputs having different transmittances, and the transmittances are ε _ND1 > ε _ND2 >. ε _NDi > ε _{NDi + 1} >. The saturation value of the measurement range of the camera output of the first filter having a higher transmittance ε _NDi for detecting the minimum value of the input light amount as> ε _{NDi + n} and the camera of the second filter having the lower transmittance ε _{NDi + 1} The minimum value of the measurement range of the output is a transmittance to wrap, and when the camera output of the first filter is saturated, the ratio of the transmittance ε _NDi and the transmittance ε _{NDi + 1} from the camera output of the second filter. From this, the correction gain of the exposure time converted into the camera output of the first filter is obtained, the input light amount is detected in the last control period, and the exposure time of the camera of the first filter is updated in the next control period. It is done.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram of the measuring apparatus using the CCD camera of Example 1. FIG.
2 is a configuration diagram of an AGC circuit part in Embodiment 1. FIG.
3 is a spectral characteristic diagram of a camera filter.
4 is a diagram illustrating a measurement range for each filter output of the camera of Example 1. FIG.
5 is a flowchart for explaining AGC operation in Example 1. FIG.
6 is a time chart for explaining the AGC operation in Example 1. FIG.
7 is a time chart for explaining the AGC operation in Example 1. FIG.
8 is a time chart for explaining AGC operation in Example 1. FIG.
9 is a time chart for explaining AGC operation in Example 1. FIG.
10 is a diagram illustrating a measurement range for each filter output of the camera of Example 2. FIG.
11 is a flowchart for explaining AGC operation in Example 2. FIG.
12 is a time chart for explaining AGC operation of a conventional CCD camera.

Best Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the drawings.

Example 1

With reference to FIGS. 1-9, the measuring apparatus 100 using the CCD camera of Example 1 is demonstrated. The measuring device 100 shown in FIG. 1 includes a detection unit 1 and a control unit 2. The detection part 1 is comprised by the CCD camera 1a for detecting the measured quantity, such as the distance with respect to the to-be-measured object 3, and the light source part 1b which irradiates a laser beam etc. In addition, in the detection part 1, the optical system according to the measurement amount is previously set.

The control unit 2 includes a control circuit 2a for setting a control cycle for obtaining a measurement amount, a memory 2b for storing camera output from a CCD camera, and a camera at an exposure time controlled within a preset control cycle. The AGC circuit part 2c which stabilizes a signal, and the calculating part 2d which calculate | requires a measurement amount from the camera data of the stabilized camera output stored are provided.

The measuring apparatus 100 provided with the CCD camera 1a changes the setting of the optical conditions of the detector 1, and the calculation algorithm performed by the control part 2 according to the measurement amount calculated | required. However, even if they change, the control of the exposure time of the AGC circuit part 2c which stabilizes the camera output from a CCD camera can respond with the same function.

Here, the shortening of the response time of the AGC will be described, taking as an example a distance measuring device that obtains a distance and obtains a distance from the steel sheet.

In FIG. 1, the distance measuring device 100 includes a light source unit 1b for irradiating a laser beam to a surface of an object to be measured 3 and a line scan type CCD camera for detecting a position of reflected light of the laser beam. The detection part 1 provided with (1a), and the control part 2 which calculate | requires the distance with the to-be-measured object 3 from the camera output of the CCD camera 1a.

The control unit 2 also includes a control circuit 2a for setting a control cycle for obtaining a measurement amount, a memory 2b for storing camera output from the CCD camera 1a, and camera data of the stored camera output. And the measured value from the camera data controlled by the AGC circuit portion 2c and the AGC circuit portion 2c which control the exposure time of the CCD camera 1a so that the camera output becomes constant by comparing the set value of the preset camera output level. And a calculating section 2d for obtaining.

Next, the detail of each part is demonstrated. The CCD camera 1a is a line scan type camera which can independently and simultaneously output the output of an RGB (red, green, blue) filter. The CCD1a1 includes an RGB filter, a CCD element, and a peripheral circuit thereof, and a CCD1a1. And an exposure time control circuit 1a3 for adjusting the amount of received light based on the exposure time setting signal transmitted from the control unit 2.

In addition, the light source unit 1b includes a laser diode (LD) 1b1 including an optical system such as a collimator that is molded into a predetermined laser beam shape on the surface of the object to be measured 3, and the power supply driving circuit 1b2. And an output setting circuit 1b3 for setting the output light amount of the laser diode 1b1.

The control unit 2 further includes a memory 2b for storing the camera output signals S _R , S _G , and S _B of the R filter, the G filter, and the B filter from the CCD camera 1a, and the stored camera output. AGC circuit portion 2c for controlling the exposure time of the CCD camera 1a so as to make the camera output constant by comparing the camera data D _R , D _G , D _B with the set value Vr of the preset camera output level, and the AGC circuit portion and a computing section (2d) to obtain the measured amount from the camera control data D _R in (2c).

In addition, the control circuit 2a generates a control period signal Sp of the measurement amount obtained by the control unit 2, supplies it to each part in the control unit 2, and stores the camera output signal from the CCD camera 1a as a memory. Control to transfer to (2b) is executed.

Next, with reference to FIG.2, FIG.3, the detailed setting of each part about the system of AGC system is demonstrated. The peak value of the wavelength of the laser beam produced by the laser diode (LD) 1b1 selects one capable of oscillating a wavelength at which the transmittance ε _R of the R filter is 90% or more, for example, 650 nm. The transmittances ε _G and ε _R of the G filter and the B filter at this time are about 5% as shown in FIG. 3.

The detailed configuration of the AGC circuit unit 2c reads camera data D _R , D _G , D _B and preset determination parameters from the memory 2b from the determination parameter setting unit 2c2 to determine an exposure time to be described later in detail. The correction gain calculation unit 2c1 obtained by calculating the correction gain α to be corrected based on the calculation flow shown in FIG. 5 and the exposure time CT set in the previous control cycle are multiplied by the correction gain α obtained by the correction gain calculation unit 2c1. and a laser output calculating section (2c4) for setting the pre-set laser output from the condition of the input amount of light reflected from the exposure time operation unit (2c3), and the measured object (3) to produce an update an exposure time setting signal S _CT.

Here, the operation principle of AGC of the distance measuring device using AGC circuit part 2c comprised in this way is demonstrated, and the detailed operation | movement is demonstrated next.

The operating principle of this embodiment is a measurement range of a high transmittance filter output that detects the minimum input light amount by simultaneously using two filter outputs of different transmittances of the CCD camera 1a in order to expand the measurement range of the input light quantity. And increase the measurement range by combining the measurement range of the low transmittance filter output for detecting the maximum input light amount, detect the input light amount in the last control cycle, and change the exposure time in the next control cycle, By controlling the output to be within the measurement range, the update time of the exposure time is shortened.

The case where this principle is applied to the CCD camera 1a provided with the above-mentioned (color) filter of RGB is demonstrated with reference to FIG. Fig. 4 shows the intensity of the input light quantity on the vertical axis as a relative value, and shows the measurement range M _R of the _R filter and the measurement range M _B of the B filter in a straight line with an arrow.

When the wavelength of the laser beam of the light source unit 1b is 650 nm, the transmittance ε _R of the R filter and the transmittance ε _B of the B filter are 18 times (= ε _R / ε _B = 90% / as shown in FIG. 3). 5%). In this case, as shown in Fig. 4, the upper limit (100%) of the measurement range of the R filter coincides with the lower limit (12%) of the B filter.

In addition, if the minimum value Pmin of the input light quantity is 20% of the measurement range M _R of the R filter, and 200 times this minimum input light quantity is the maximum value Pmax, the input light quantity can be known up to the upper limit of the B filter. However, with respect to the input light amount exceeding the upper limit value of the B filter, it can be discriminated only whether or not it is exceeded.

Moreover, if it is in the measurement range of B filter, the input light quantity can be calculated | required as the input light quantity converted into the value of R filter. Therefore, the exposure time of an R filter can be calculated | required simultaneously by knowing the input light quantity of B filter.

In addition, the measurement range M _R of the input light amount of the R filter is set in advance according to the optical setting conditions of the detector 1. For example, the reflection characteristics of the object 3 to be measured and the brightness (efficiency) of the optical system of the detector 1 capable of receiving light are set in advance, and the control period for obtaining the detection sensitivity and the measured value of the CCD camera 1a is determined. The minimum value and the maximum value of the amount of input light which can be received from the measurement object 3 are predicted.

Then, the laser output and the exposure time CT of the CCD camera 1a for the minimum input light amount are set. Here, the minimum value Pmin of the amount of input light predicts that the output of the R filter of the CCD camera 1a is 20%, which is two times or more the noise level, and the maximum value is 40, which is a relative value of 200 times the minimum input light amount. do.

Next, the operation of the AGC circuit section 2c based on this principle will be described with reference to FIGS. 5 to 9. Fig. 5 is a flowchart showing the operation of calculating the correction gain? For updating the exposure time CT of the AGC circuit section 2c.

5, the camera data D _R, D _B, respectively, R filter, represents the output of the B filter, in the case where the measurement range is compared to the value of the camera data D _R of 80% of M _R, written as D _R80 Let's do it.

In addition, the setting value and determination parameter shown in FIG. 5 are previously memorize | stored in the determination parameter setting part 2c2 shown in FIG.

First, the initial values of the exposure time CT and the laser output are set for the CCD camera 1a and the light source unit 1b from the exposure time calculating section 2c3 and the laser output calculating section 2c4, respectively (s1).

Next, the camera data D _R and D _B are read from the memory 2b (s2), and it is determined whether the camera data D _R is saturated (s3). If it is determined not to be saturated, it is again determined whether the camera data is within a range of a predetermined set value (control target value) (D _R80 ≥ D _R ≥ D _R70 ) (s4), and in that case, exposure The operation proceeds to the next operation without updating the time (s4-Y).

When it is determined out of the range (s4-N), the correction gain α1 (= Vr / D _R ) with respect to the set value Vr is obtained (s5). Then, the exposure time CT1 (= CTi × α1, CTi = exposure time before updating) corresponding to the obtained correction gain α1 is obtained from the exposure time calculating section 2c3, and the exposure time setting signal S _CT is sent to the CCD camera 1a ( s6).

Next, when it is determined that the camera data D _R is saturated (s3-Y), it is determined whether the camera data D _B is saturated (s7). If the camera data D _B are not saturated, also, if the camera data D _B (for example, 10% of the camera data D _B) the lower limit of the measuring range is determined whether or less, and (s8), or (s8-N ), in terms of the value of the camera data to the camera data D _{B R} D, obtains the correction gain _{α2 (= Vr / (D B} · ε R / ε B) for the camera data D _R) (s9).

The exposure time CT2 (= CTi × α2, CTi = exposure time before updating) corresponding to the obtained correction gain α2 is obtained from the exposure time calculating section 2c3, and the exposure time setting signal S _CT is sent to the CCD camera 1a (s6). ).

If so (s8-Y), that is, if the camera data D _B is less than or equal to the lower limit of the measurement range, select the preset correction gain α3, for example 1/2, in which the camera data D _{R at} this time becomes the measurement range. (S10), the exposure time CT3 (= CTi x alpha 3, CTi = exposure time before updating) corresponding to the selected correction gain alpha 2 is obtained by the exposure time calculating unit 2c3. Then, the obtained exposure time setting signal S _CT is sent to the CCD camera 1a (s6), and the camera data D _R in the control period in the updated exposure time setting signal S _CT is checked to determine the range of the set value. If is exceeded, the exposure time setting signal S _CT is updated in the next control period (s3-s4-s5).

Next, when the camera data D _B is saturated (s7-Y), the preset correction gain α4, for example, 1/50, in which the camera data D _{R at} this time becomes the measurement range is selected (s11), The exposure time CT4 (= CTi × α4, CTi = exposure time before updating) corresponding to the selected correction gain α4 is obtained by the exposure time calculating unit 2c3. Then, the obtained exposure time setting signal S _CT is sent to the CCD camera 1a (s6), and the camera data D _R in the control period in the updated exposure time setting signal S _CT is checked to determine the range of the set value. If is exceeded, the exposure time setting signal S _CT is updated in the next control period (s3-s4-s5).

The selected correction gains α3 and α4 are selected here as 1/2 and 1/50, respectively, but when the camera data D _B exceeds the lower limit or the upper limit of the measurement range, the assumed amount of input light is determined by the camera data D _R. As long as it is a value in a range, this value may be any.

Next, with reference to the flow of FIG. 5, the example of the calculation operation of four types of correction gains is demonstrated using the time chart. FIG. 6 is a time chart of the calculation in the case of obtaining the correction gain α1 when the output of the R filter of the CCD camera 1a is not saturated.

The camera data is detected in the control period S _P0 it is, is read out in the next control period S _P1, and also, obtains the correction gain α1 in the next control period S _P2 of, by requiring three times the control cycle, the updated exposure The camera data D _R1 at time C _T1 is obtained.

Further, when the camera data D _{R0 at} this time is 30% of the relative light amount shown in Fig. 4, when the set value Vr is 75%, the correction gain α1 is 2.5, and if this input light amount does not change, the exposure time is The corrected camera data D _{R 1} output is 75% after three times the control period.

7 is a time chart of the calculation in the case of obtaining the correction gain α2 when the output of the R filter of the CCD camera 1a is saturated.

The camera data is detected in the control period _P0 is S, it is read out in the next control period S _P1, and also, obtains the correction gain α2 in the next control period _P2 of the S. In this case, three times the control period is required, and thus the camera data D _R2 at the updated exposure time CT1 is obtained.

Further, when the camera data D _R is 540% of the relative light amount shown in Fig. 4 (s8, s9), the correction gain α2 is 0.139, and if this input light amount does not change, the camera data D _{R 2} whose exposure time is corrected The output becomes 75% after three times the control period.

8 is a time chart of the calculation when the correction gains α3 and α1 are obtained when the output of the R filter of the CCD camera 1a is saturated and the output of the B filter is equal to or lower than the lower limit.

The camera data detected in the control period S _P0 is read out in the next control period S _P1 , and the correction gain α3 is obtained in the next control period S _P2 .

Then, the to require three times the control period, the camera data D _R31 in the updated exposure time CT31, In addition, the camera data D _R31 is not in the measuring range, to require a control cycle of three times, to update the exposure The camera data D _R32 corrected at time CT32 is obtained.

In this case, when the camera data D _R is 100% in the relative light amount shown in FIG. 4 and the camera data D _B is 5.6% in the relative light amount (s8, s10), the correction gain α3 is 0.5. And, if the input light amount change, it can be obtained Further, after the exposure time to the exposure time required CT31 6 times the update to CT32, and controls the camera calibration data D _{R 32} cycles.

9 is a time chart of the calculation when the correction gains alpha4 and alpha1 are calculated when the output of the R filter of the CCD camera 1a is saturated and the output of the B filter is saturated again.

The camera data detected in the control period S _P0 is read out in the next control period S _P1 , and the correction gain α4 is obtained in the next control period S _P2 . Then, the required three times the control period, the camera data in the updated exposure time CT41 D _R41 is, also, a camera data D _R41 is not in the measuring range, to require a control cycle of three times, the updated exposure The camera data D _R42 corrected at time CT42 is obtained.

In this case, when the camera data D _R is 1800% in the relative light amount shown in FIG. 4 and the camera data D _B is 100% in the relative light amount (s8, s11), the correction gain α4 is 0.02. If the input light amount does not change, the exposure time CT41 is further updated to the exposure time CT42 to obtain the corrected camera data D _{R 42} after requiring six times the control period.

In addition, although the B filter was selected and demonstrated as one filter of different transmittance | permeability in this Example, when the wavelength of the selected laser beam is 650 nm even if G filter is used, the same effect is acquired.

As described above, according to the present embodiment, in order to enlarge the measurement range of the input light amount, two filter outputs having different transmittances of the CCD camera 1a are simultaneously used, and a high transmittance for detecting the minimum value of the input light amount is high. The measurement range is expanded by combining the measurement range of the filter output and the measurement range of the filter output with low transmittance, detecting the amount of input light in the last control cycle, and updating the exposure time of the filter output with high transmittance in the next control cycle. Therefore, the exposure time can be updated quickly even if the variation range of the input light amount is large.

That is, according to the present embodiment, a measurement apparatus capable of obtaining a CCD camera signal that can be measured in the shortest time with respect to an excessive amount of input light exceeding a saturated exposure amount of a CCD camera in an exposure time within a preset control cycle time, and It is possible to provide a method for shortening the response time.

[Example 2]

10 and 11, a second embodiment will be described. About Example 2, the same code | symbol is attached | subjected to Example 1 and the description is abbreviate | omitted.

The difference between Example 2 and Example 1 is that, in Example 1, an RGB color filter was used as a filter for expanding the measurement range of the input light quantity, but in Example 2, spectroscopy was used instead of RGB color filter. The difference is that three different transmittance neutral density filters, filters ND0, ND1, and ND2, each having a flat transmittance, are used.

In detail, as shown in FIG. 10, the CCD camera 1a is a camera which can obtain the output for every ND filter of several different transmittance | permeability of a line scan type | mold. ND filter is configured to filter ND0, filters ND1, filter ND2 of the transmission factor ε _ND2 of the transmission factor ε _ND1 of the transmission factor ε _ND0 and, also, the transmission size of each, ε _ND0> ε _ND1> ε _ND2, also, the filter ND0 The transmittance at which the maximum value (saturation value) of the measurement range and the lower limit value of the measurement range of the filter ND1, and the maximum value of the measurement range of the filter ND1 and the lower limit value of the measurement range of the filter ND2 are respectively wrapped.

For example, when the values of the transmittances are selected as values of ε _ND0 = 1.0, ε _ND1 = 1/8, and ε _ND2 = 1/8 ² , the filter ND0 can receive the minimum value of the input light without being diminished. . The lap amount of the measurement range between the filters is the maximum value of the measurement range of the filter ND0, the lower limit value of the measurement range of the filter ND1, and the measurement range of the filter ND1 when the measurement range of each filter is 100% to the minimum value of 10%. Each lap length of the maximum value of and the lower limit of the measurement range of the filter ND2 becomes 2%, and the three filters allow the measurement range of the input light quantity (relative value) to 0.2 to 64.

According to the setting conditions of the CCD camera 1a configured as described above, as shown in Fig. 11, even when the change in the input light quantity is 320 times (= 64 / 0.2), the value can be detected from the output of any filter. . Therefore, the calculation of the correction gain in the AGC circuit section 2c is any one of three types, and the calculation of the correction gain is performed in one circuit.

Hereinafter, the control operation of the AGC circuit unit 2c will be described with reference to the calculation flow for obtaining the correction gain in FIG. 11. In Fig. 11, the camera data D ₀ , D ₁ , D ₂ represent the outputs of the filter ND0, the filter ND1, and the filter ND2 read out from the memory 2b, respectively, and the comparison value of the camera data D ₀ is the measurement range. In the case of 80% of M _ND0 , it will be described as D ₀₈₀ .

In addition, the setting value and determination parameter shown in FIG. 11 are previously memorize | stored in the determination parameter setting part 2c2 shown in FIG.

First, initial values of the exposure time CT and the laser output are set for the CCD camera 1a and the light source unit 1b from the exposure time calculating section 2c3 and the laser output calculating section 2c4, respectively (s1).

Next, the camera data D ₀ , D ₁ , and D ₂ are read from the memory 2b (s2), and it is determined whether the camera data D ₀ is saturated (s3). If it is determined that it is not saturated, it is again determined whether the camera data is within a predetermined setting value Vr (control target value) (D ₀₈₀ ≥ D ₀ ≥ D ₀₇₀ ), in which case, The operation proceeds to the next operation without updating the exposure time (s4-Y).

When it is determined out of the range (s4-N), the AGC circuit unit 2c1 obtains a correction gain α11 (= Vr / D0) by calculating the ratio of the set value Vr of the camera output level and the output D ₀ of the ND filter. Further, the exposure time CT11 (= CTi × α11) corresponding to the obtained correction gain α11 is obtained, and the exposure time CTi before correction is updated to the exposure time CT11 (s6).

When the camera output of the filter ND0 is saturated, the saturation and unsaturated of the camera output of the filter ND1 are further determined (s7). When the camera output of the filter ND1 is unsaturated, from the ratio (ε _ND0 / ε _ND1 ) of the set value Vr to the output D ₀ of the filter ND0 with respect to the camera output D ₁ of the filter _ND1 , the correction gain _α12 (= Vr / (D ₁ · ε _ND0 / ε _ND1 )). Further, the exposure time CT12 (= CTi x? 12) corresponding to the obtained correction gain? 12 is obtained (s8), and the exposure time CTi before correction is updated to the exposure time CT12 (s6).

Further, when the camera output of the filter ND1 is saturated, the correction gain α13 (= Vr /) from the ratio (ε _ND0 / ε _ND2 ) between the set value Vr and the output D ₀ of the filter ND0 with respect to the camera output D ₂ of the filter _ND2 . (D ₂ · ε _ND0 / ε _ND2 )) is obtained (s9).

Further, the exposure time CT13 (= CTi × α13) corresponding to the obtained correction gain α13 is obtained, and the exposure time CTi before correction is updated to the exposure time CT13 (s6).

That is, when there is an excessive amount of input light that saturates the camera output of the filter ND0 of the CCD camera, the degree of the correction is obtained by calculating the correction gain for the filter ND0 from the camera output of the filter ND1 or the camera output of the filter ND2. Since the measurement can be performed by the change of, the response time can be shortened even when the measurement range of the input light quantity changes drastically.

In addition, although some embodiment of this invention was described, these embodiment is shown as an example and is not intending limiting the range of invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention. These embodiments and variations thereof are included in the scope and spirit of the invention, and included in the range equivalent to the invention described in the claims.

1: detection unit
1a: CCD camera
1a1: CCD
1a2: ADC
1a3: exposure control circuit
1b: light source
1b1: LD
1b2: power drive circuit
1b3: output setting circuit
2: control unit
2a: control circuit
2b: memory
2c: AGC circuit
2c1: correction gain calculator
2c2: Judgment parameter setting unit
2c3: exposure time calculator
2c4: laser output calculator
2d: calculator
3: measuring object
100: measuring device

Claims (4)

A detection unit including a light source unit for irradiating a laser beam to the surface of the object to be measured, a line scan type CCD camera for detecting reflected light of the laser beam, and a measurement amount such as the shape of the measured object from the output of the CCD camera A measuring device having a control unit,
The control unit generates a control period signal of the measurement amount obtained by the control unit, supplies the control cycle signal to each unit in the control unit, and inputs and transmits a camera output signal of the CCD camera. The control period of the CCD camera so as to make the camera output constant by comparing a memory for storing a camera output signal transmitted from a control circuit with a camera camera of the stored camera output signal and a preset camera output level setting value. An AGC circuit section for controlling an exposure time set within a time of; and a calculation section for obtaining the measurement amount from the CCD data controlled by the AGC circuit section;
The CCD camera is a camera that can simultaneously obtain outputs for each of the ND filters having different transmittances of the line scan type, and the ND filter is a first ND filter _having a transmission ε _ND0 and a second ND having a transmission ε _ND1 . Filter, the third ND filter of transmittance ε _ND2 ,
The magnitude of the transmittance is ε _ND0 > ε _ND1 > ε _ND2 , and the lower limit of the saturation value of the camera output of the first ND filter and the measurement range of the second ND filter, and the saturation value of the second ND filter. And the lower limit values of the measurement range of the third ND filter are each wrapped as transmittance,
The AGC circuit unit determines whether the camera output of the first ND filter is saturated, and if unsaturated, obtains a ratio between the set value of the camera output level and the output D ₀ of the first ND filter to obtain a first correction gain. (alpha) 1 is calculated | required, Furthermore, the exposure time corresponding to the obtained 1st correction gain is calculated | required, and the exposure time before correction is updated to the said exposure time,
When the camera output of the first ND filter is saturated, and the saturation and unsaturated of the camera output of the second ND filter are determined, and the camera output of the second ND filter is unsaturated, the second ND filter 2 For camera output D ₁ , a second correction gain is obtained from the ratio of the set value and the output D ₁ of the first ND filter, and an exposure time corresponding to the obtained second correction gain is obtained to determine the exposure time before correction. Is updated to the exposure time,
When the camera output of the second ND filter is saturated, for the camera output D ₂ of the third ND filter, a third correction gain is obtained from the ratio between the set value and the output of the first ND filter. The exposure time corresponding to the obtained third correction gain is obtained, and the exposure time before correction is updated to the exposure time;
When there is an excessive amount of input light that saturates the camera output of the first ND filter of the CCD camera, the degree is set from the camera output of the second ND filter or the camera output of the third ND filter. Find the correction gain for
A measuring device using a CCD camera, characterized in that the measurement is made possible by changing the exposure time once. A detection unit including a light source unit for irradiating a laser beam to the surface of the object to be measured, a line scan type CCD camera for detecting a position of reflected light of the laser beam, and a measurement amount such as the shape of the measurement object from the output of the CCD camera A measuring device having a control unit for obtaining
The control unit generates a control period signal of the measurement amount obtained by the control unit, supplies it to each unit in the control unit, and inputs and transmits a camera output signal of the CCD camera, and is transmitted from the control circuit. The memory for storing the camera output signal is compared with the stored camera data of the camera output signal and a preset camera output level setting value, and is set within the time of the control cycle of the CCD camera so that the corresponding camera output is constant. An AGC circuit section for controlling the exposure time to be obtained, and a calculation section for obtaining a measurement amount from the CCD camera controlled by the AGC circuit section,
The CCD camera is a color camera having a line scan type RGB filter,
The peak value of the wavelength of the laser beam selects a wavelength at which the transmittance ε _R of the R filter is 90% or more,
The AGC circuit section determines whether or not the camera output of the R filter is saturated, and if unsaturated, obtains a ratio of the camera output set value and the output D ₀ of the R filter as the first correction gain. Obtain an exposure time corresponding to the first correction gain, update the exposure time before correction to the exposure time,
When the camera output of the R filter is saturated, the saturation and unsaturated of the camera output of the B filter are determined, and when the camera output of the B filter is unsaturated and is lower than or equal to the lower limit of the measurement range, the camera of the B filter. With respect to the output, a value obtained by multiplying the set value by the ratio of the transmittances of the B filter and the R filter is obtained to obtain a second correction gain, and to obtain an exposure time corresponding to the obtained second correction gain to obtain an exposure before correction. Update the time to the exposure time,
In the case of desaturation and in the measurement range, in the case of conversion to the camera output of the R filter, the preset third correction gain which becomes the output level of the measurement range is selected, and the exposure time corresponding to the third correction gain is obtained. Update the exposure time before correction;
When the camera output of the B filter is saturated, the preset fourth correction gain which becomes the measurement area when converted to the camera output of the R filter is selected, and the exposure time corresponding to the fourth correction gain is obtained to determine the Update the exposure time to the exposure time,
When the input light amount of the CCD camera is an excessive input that saturates the camera output of the R filter, the first to the fourth from the ratio of the transmittances of the B filter and the R filter to the camera output of the B filter. A correction device is used to determine the exposure time at which the camera output of the R filter is set to a preset value. The method of claim 2,
A measuring device using a CCD camera which has been used as the output of the G filter instead of the output of the B filter. As a shortening method of the response time of the measuring apparatus 100 which controls the exposure time of a CCD camera within the time of a preset control period,
The CCD camera is a camera capable of simultaneously obtaining two or more filter outputs having different transmittances,
The transmittance is ε _ND1 > ε _ND2 >. ε _NDi > ε _{NDi +1} >. > ε _{NDi + n} ,
The saturation value of the measurement range of the camera output of the first filter having the higher transmittance ε _NDi that detects the minimum value of the input light amount is wrapped and the minimum value of the measurement range of the camera output of the second filter having the lower transmittance ε _{NDi + 1} is wrapped. Let transmittance to say,
When the camera output of the first filter is saturated, the exposure converted from the camera output of the second filter or the ratio of the transmittance ε _NDi and the transmittance ε _{NDi +1} to the camera output of the first filter. Find the correction gain of time
A method of shortening the response time of a measuring device using a CCD camera, wherein the amount of input light is detected in a previous control period, and the exposure time of the camera of the first filter is updated in the next control period.

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