JP3960108B2 - Optical information reader - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical information reader having a microprocessor capable of changing the processing speed.
[0002]
[Problems to be solved by the invention]
In recent years, products equipped with a microprocessor whose operation clock can be changed have been supplied as a barcode handy terminal. By changing the operation clock, it is possible to match the performance required by the user. For example, when requesting higher speed processing, the operation clock is set to a higher speed, and when requesting operation for a longer time, the operation clock is set to a lower speed. Also, the decoding time varies according to the operation clock of the microprocessor, and if the operation clock is fast, the decoding time is short, and if it is slow, the decoding time is long. This decoding time can be predicted by the set operation clock and the code type.
[0003]
FIG. 8 shows a conventional reading operation. In FIG. 8, for example, when decoding a barcode imaged by the line sensor, the microprocessor alternately executes an exposure process for exposing the line sensor and a capture process for capturing the output from the line sensor, The decoding process for decoding the fetched data is processed in parallel. In this case, while the exposure time and the capture time are determined by the specifications of the line sensor, the decoding time varies depending on the operation speed of the microprocessor as described above, so that depending on the decoding time, as shown in FIG. A plurality of exposure processes and capture processes may be executed in parallel within the decoding time. For this reason, the processes other than the final exposure process and capture process within the decode time (exposure process and capture process immediately before decoding) are useless, and the current consumption increases accordingly.
[0004]
The present invention has been made in view of the above circumstances, and an object thereof is to provide a microprocessor with a variable processing speed that performs parallel processing of exposure processing and capture processing for the next reading while decoding the read optical information. Another object of the present invention is to provide an optical information reading apparatus that can prevent unnecessary exposure processing and capture processing from being executed.
[0005]
[Means for Solving the Problems]
According to the first aspect of the present invention, when the optical information is read, the microprocessor executes an exposure process for exposing the optical information reading sensor by controlling the driving unit, and then performs the exposure processing from the optical information reading sensor. The binarization unit binarizes the output of the output and fetches the binarized data, and decodes the binarized data. At this time, the microprocessor executes the exposure process and the capture process in parallel while decoding the optical information. In this case, although the exposure time and the capture time are constant, the decoding time varies depending on the operation speed of the microprocessor. For this reason, there are cases where a plurality of exposure processes and capture processes are executed during the decode time, and there is a possibility that other than the final exposure process and capture process during the decode time will be wasted.
Here, since the microprocessor executes the exposure process and the capture process only once during the decoding time, the exposure process and the capture process are not performed wastefully, and the current consumption can be reduced. .
[0006]
Further , the microprocessor predicts the time required for decoding from its own operation speed, and obtains an adjustment time obtained by subtracting the exposure time required for the exposure processing and the acquisition time required for the acquisition processing from the predicted decoding time. In this case, since the decoding time is a time obtained by adding the exposure time, the capture time, and the adjustment time, the exposure process and the capture process are performed in sequence when the adjustment time has elapsed from the start of decoding, so that the exposure is performed during the decode time. The process and the capture process can be executed only once. Furthermore, when the number of decoded data is less than the original number of data, the microprocessor determines that the user is not reading and increases the predicted decoding time, thus increasing the reading interval and reducing the current consumption. Can be reduced.
[0007]
According to the second aspect of the present invention, when the decoding is started, the microprocessor executes the exposure process and then extends the capture process by the adjustment time, so that the exposure process and the capture process are performed during the decode time. Can be executed only once.
[0008]
According to the invention of claim 3 , since the time required for decoding is stored and used as the predicted decoding time, the exposure processing is performed during the decoding time even when the predicted decoding time is different from the actual decoding time. And the capture process can be executed only once.
[0010]
According to the fourth aspect of the present invention, since the microprocessor drives the illumination unit during the exposure process, the consumption current can be greatly suppressed while the illumination unit is used.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a barcode handy terminal (corresponding to an optical information reading sensor) will be described with reference to FIGS.
The bar code handy terminal 1 is composed mainly of a microprocessor 2. The illumination LED 3 is a red light emitting diode, and uniformly illuminates the barcode label 4 to be read in response to a command from the microprocessor 2. The reflected light from the barcode label 4 is converged by the lens 5 and formed on the line sensor 6. A line sensor (corresponding to an optical information reading sensor) 6 is a one-dimensional black-and-white image sensor in which a large number of photodiodes having spectral sensitivity are arranged in a straight line near the emission spectrum of the illumination LED 3, and is a driving circuit (corresponding to a driving means). ) It is driven by the shift pulse and shift clock given from 7. The shift pulse is a signal for transferring the charge accumulated in the line sensor 6 to the shift register, and the interval between the shift pulses becomes the exposure time of the line sensor scan. The shift clock is a signal for outputting the charge from the shift register as a sensor output. That is, in order to read the bar code by the line sensor 6, two driving cycles of exposure time and capture time are required.
An output signal from the line sensor 6 is binarized by a binarization circuit (corresponding to binarization means) 8 and is decoded into bar code information by being taken in by the microprocessor 2.
[0012]
The key 9 is used to input a start timing for starting barcode reading, for example, a date and time. The buzzer 10 is used for notifying completion of barcode reading or for warnings such as a battery voltage drop. The LCD 11 displays guidance to the user, barcode reading data, and the like. The communication port 12 is used to transfer accumulated data such as barcode data to the host computer. The memory 13 stores a program for operating the barcode handy terminal 1 and decoded barcode data. The power supply circuit 14 supplies the voltage from the battery 15 in a state where it is boosted for each circuit block.
[0013]
Next, the operation of the above configuration will be described.
When the user operates the trigger key of the keys 9, the microprocessor 2 of the barcode handy terminal 1 reads the barcode information.
FIG. 2 shows a reading routine by the microprocessor 2 of the bar code handy terminal 1. In FIG. 2, the microprocessor 2 first performs an initial setting (S101). In this initial setting, the processing flag and the initial value of the adjustment time described later are set. In this case, “exposure” is set as the processing flag, and a default value is set as the adjustment time.
Next, power is turned on to the line sensor 6, the drive circuit 7, the binarization circuit 8, etc. (S102).
[0014]
Next, in order to discharge unnecessary charges accumulated in the line sensor 6, the drive circuit 7 generates a shift pulse and a shift clock from the line sensor 6 to perform the initial sweep and a specified time required for the initial sweep. Minute timer interrupt is set (S103). In this case, the shift pulse supplied from the drive circuit 7 to the line sensor 6 is one pulse, the shift clock is a repetitive clock of multivibrator oscillation, and the electric charge accumulated in the photosensitive part of the line sensor 6 corresponds to the shift pulse. In addition to being transferred to the shift register, the electric charge transferred to the shift register is output to the outside in accordance with the shift clock, whereby initial sweep is performed (initial sweep shown in FIG. 7).
[0015]
Next, the microprocessor 2 waits for an interrupt (S104), and waits in this step S104 until a timer interrupt in the above-described step S103 or a key interrupt for a key operation by the user occurs. Then, when a timer interrupt occurs at the initial sweep specified time set in step S103, a timer interrupt process is performed.
[0016]
FIG. 3 shows timer interrupt processing by the microprocessor 2. This timer interrupt process is for determining a process to be executed when a timer interrupt occurs. In FIG. 3, the microprocessor 2 branches to the processing to be performed from now on according to the current processing flag (S201). Initially, since “exposure” is set in step S101 of the reading routine, exposure processing is executed (S202).
[0017]
FIG. 4 shows an exposure process by the microprocessor 2. This exposure process is for sweeping out the previous unnecessary exposure and for accumulating charges in the line sensor 6 for a specified exposure time in order to read the barcode. In FIG. 4, after turning on the illumination LED 3 (S301), the microprocessor 2 generates a shift pulse with the shift clock temporarily stopped from the drive circuit 7 (S302). Thereby, the electric charge accumulated in the photosensitive part of the line sensor 6 is transferred to the shift register, and the exposure process is started.
[0018]
Next, a timer interrupt with an exposure time Xms is set (S303), a shift clock is generated from the drive circuit 7 (S304), and the next process "take-in" is set as a process flag (S305). Thereby, unnecessary exposure transferred to the shift register can be swept out.
[0019]
When the exposure process is finished and the timer interrupt is finished, the microprocessor 2 branches the end of the reading process itself from the standby state in the reading routine shown in FIG. 2 (S105). The condition for ending is when the decoding is completed or when reading is interrupted by the user releasing the trigger switch or the like, and when the reading is not finished (S105: NO), it is determined whether there is captured data (S106). At the time of sweeping out the unnecessary exposure described above, since there is no fetched data (S106: NO), it enters a standby state waiting for an interrupt (S104).
[0020]
When the timer interrupt Xms time set in the above-described exposure process elapses, a timer interrupt occurs again in the interrupt routine, and the process proceeds to the timer interrupt process shown in FIG. At this time, since the processing flag is “take-in”, the take-in process is performed (S203).
[0021]
FIG. 5 shows the capturing process performed by the microprocessor 2. This take-in process is for taking in the charges accumulated in the previous exposure process. In FIG. 5, after turning off the illumination LED 3 (S401), the microprocessor 2 generates a shift pulse with the shift clock temporarily stopped (S402). Thereby, the electric charge accumulated in the photosensitive part of the line sensor 6 is transferred to the shift register, and the capturing process is started.
[0022]
Next, after setting a timer interrupt for the capture time Yms (S403), a shift clock is generated (S404), the next process "adjustment" is set in the process flag (S405), and then the data capture (S406). Data acquisition is performed by a method that does not put a load on the microprocessor 2 by, for example, processing by a DMA function or a gate array.
[0023]
When the capture process is finished and the timer interrupt is finished, the microprocessor 2 branches the end of the read process itself from the standby state in the read routine shown in FIG. 2 (S105). If not completed (S105: NO), in the state where the above-described exposure process has been completed, since there is captured data (S106: YES), data decoding is executed (S107).
[0024]
At this time, when the timer interrupt Yms time elapses and a timer interrupt occurs again, an adjustment process is executed because the process flag is “adjustment” in the timer interrupt shown in FIG. 3 (S204). That is, the adjustment process is executed simultaneously with the start of the decoding.
[0025]
FIG. 6 shows adjustment processing by the microprocessor 2. This adjustment process provides an adjustment time during which neither the exposure process nor the capture process is executed from the start of decoding. The decode time is predicted as will be described later, and the exposure time and the capture time are subtracted from the decode time. . In FIG. 6, after turning off the illumination LED 3 (S501), the microprocessor 2 generates a shift pulse with the shift clock temporarily stopped from the drive circuit 7 (S502). Thereby, the unnecessary exposure of the line sensor 6 is transferred to the shift register.
[0026]
Next, a timer interrupt of the adjustment time Zms is set (S503), a shift clock is generated from the drive circuit 7 (S504), and the next process "exposure" is set as a process flag (S505). Thereby, unnecessary exposure of the shift register of the line sensor 6 is swept out (adjustment time 1 shown in FIG. 7).
[0027]
When the adjustment process as described above is completed and the timer interrupt Zms time has elapsed, a timer interrupt is generated again. At this time, since the process flag is “exposure” in the timer interruption shown in FIG. 3, the exposure process is selected and the above-described exposure process is executed (exposure time 2 shown in FIG. 7).
[0028]
In addition, when the timer interruption Xms time has elapsed after the exposure process is completed, a timer interruption occurs again. At this time, since the processing flag in the timer interrupt shown in FIG. 3 is “take-in”, the take-in process is selected and the above-described take-in process is executed (take-in time 2 shown in FIG. 7), and the timer interrupt Yms is set. To do.
[0029]
Here, since the adjustment time is a time obtained by subtracting the exposure time and the capture time from the predicted decoding time as will be described later, the timer interrupt Yms time elapses at the same time as the decoding ends, and the microprocessor 2 The adjustment process is executed simultaneously with the start of the next decoding.
When the decoding process is completed, the decoding process is completed when the decoding process is completed. If the decoding process is not completed, the decoding process is performed using the next fetched data.
[0030]
By the way, the barcode handy terminal 1 of this embodiment is equipped with a microprocessor 2 capable of changing the operation clock. When a high-speed process is required, the operation clock is set to a high speed and a longer operation is required. When doing so, the operation clock is set to a low speed. In this case, the decoding time also varies according to the speed of the operation clock of the microprocessor 2, and if the operation clock is fast, the decoding time is short, and if it is slow, it becomes long.
[0031]
However, the above-described adjustment time Zms is set to absorb the variation in the decode time. When the adjustment time Z> 0, the decode time = exposure time X + acquisition time Y + adjustment time Z. Only when Z = 0, the relationship of decoding time = exposure time X + capture time Y is established.
[0032]
FIG. 7 shows the drive timing of the line sensor 6. FIG. 7 shows a case where decoding time = exposure time + acquisition time + adjustment time (Z> 0). Since the conventional method shown in FIG. 8 does not have the above-described adjustment time, unnecessary exposure time and capture time are generated, whereas in this embodiment, unnecessary exposure time and capture time are generated. It can be seen that this can be prevented.
[0033]
According to such an embodiment, in the microprocessor 2 that processes the exposure process and the capture process in parallel while decoding the read barcode, the exposure process and the capture process are executed only once within the decoding time. As a result, useless exposure processing and capture processing are not executed, and the consumption of the microprocessor 2 is different from the conventional example in which exposure processing and capture processing are executed a plurality of times within the decoding time. The current can be reduced.
[0034]
Moreover, although the operation speed can be changed, the microprocessor 2 predicts the decode time from its own operation speed, obtains an adjustment time obtained by subtracting the exposure process and the capture time from the predicted decode time, and starts decoding. Since the exposure process and the capture process are sequentially executed when the adjustment time has elapsed, the exposure process and the capture process can be performed only once within the decoding time.
[0035]
( Reference embodiment)
Next, a reference embodiment will be described. This reference embodiment is characterized in that unnecessary exposure processing and capture processing are not executed within the decoding time by adjusting the capture time.
That is, in the first embodiment, the adjustment time is provided within the decoding time. However, by setting the time including the adjustment time as the capture time, the same effect as the first embodiment can be obtained. To get. In this case, when adjustment time Z> 0, decode time = exposure time X + capture time (Y + Z). Only when adjustment time Z = 0, the relationship of decode time ≦ exposure time X + capture time Y is established.
According to such an embodiment, the adjustment can be performed only by adjusting the capture time without providing the adjustment time as in the first embodiment.
[0036]
The present invention is not limited to the first embodiment, and can be modified or expanded as follows.
Instead of using a value set in the memory in advance as the predicted decoding time, the actual decoding time may be stored and used as the predicted decoding time. That is, the decoding time can be predicted by the cycle of the operation clock of the microprocessor 2 and the decoding code type to be read, but the decoding time is affected by the code length (number of digits) and the state of the label. Accuracy can be increased by using the previous actual decoding time.
[0037]
If it is determined that the barcode cannot be clearly formed by the number of bars taken in by the microprocessor 2, that is, if the user is not trying to read the barcode label, the adjustment time and therefore the predicted decoding time are increased. The current consumption may be reduced by increasing the interval at which the reading operation is performed.
[0038]
Within the decoding time, the adjustment process may be executed subsequent to the exposure process and the capture process, or the capture process may be performed after the adjustment process is performed following the exposure process.
When the line sensor has an electrical shutter function, the illumination LED may be held in a lighting state.
A two-dimensional sensor may be used instead of the line sensor.
[Brief description of the drawings]
FIG. 1 is a block diagram schematically showing an overall configuration according to a first embodiment of the present invention. FIG. 2 is a flowchart showing a read routine by a microprocessor. FIG. 3 is a flowchart showing timer interrupt processing by a microprocessor. 4] Flow chart showing the exposure process by the microprocessor [FIG. 5] Flow chart showing the capture process by the microprocessor [FIG. 6] Flow chart showing the adjustment process by the microprocessor [FIG. 7] FIG. FIG. 8 is a diagram corresponding to FIG. 7 showing a conventional example.
1 is a barcode handy terminal (optical information reader), 2 is a microprocessor, 3 is an illumination LED (illumination means), 4 is a barcode label, 6 is a line sensor (optical information reader), 7 is a drive circuit (Drive means) 8 is a binarization circuit (binarization means).

Claims (6)

An optical information reading sensor for imaging optical information;
Driving means for driving the optical information reading sensor;
Binarization means for binarizing the output from the optical information reading sensor;
An exposure process for exposing the optical information reading sensor by controlling the driving unit is executed, and then an acquisition process for binarizing the output from the optical information reading sensor by the binarizing unit and taking in the output In an optical information reading apparatus comprising a microprocessor capable of executing processing and changing the exposure speed and the capture process in parallel while decoding the binarized data captured by the capture process and processing the capture process in parallel,
The microprocessor executes the exposure process and the capture process only once during the decoding time, and predicts the time required for decoding from its own operation speed. From the predicted decoding time, the exposure time required for the exposure process and An adjustment time obtained by subtracting the acquisition time required for the acquisition process is obtained, and the exposure process and the acquisition process are sequentially performed when the adjustment time has elapsed from the start of the decoding, and the number of decoded data is more than the original number of data. In the case where the number is small, the optical decoding device is characterized in that the prediction decoding time is lengthened . When the microprocessor starts executing the decoding, instead of sequentially executing the exposure process and the capture process when the adjustment time has elapsed from the start of the decode , the microprocessor executes the exposure process and then performs the capture. The optical information reading apparatus according to claim 1 , wherein the process is executed by extending the adjustment time . 3. The optical information reading apparatus according to claim 1 , wherein the microprocessor stores a time required for decoding and sets the predicted decoding time . Provide lighting means,
4. The optical information reading apparatus according to claim 1 , wherein the microprocessor drives the illumination unit during the exposure process . 5. The optical information reading apparatus according to claim 1, wherein the optical information reading sensor is a line sensor . Optical information reading apparatus according to any one of claims 1 to 4, wherein the optical information reading sensor is a two-dimensional sensor

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