JPS6224774A - Image scanner device - Google Patents

Abstract

PURPOSE:To make an image scanner device handling the presence/absence of white/black levels only without expression of an intermediate density express a pseudo multi-value with an inexpensive means by adopting the constitution that a noise signal is applied to an analog signal output from an optical read section and the result is compared with a threshold voltage. CONSTITUTION:An analog signal representing the density of a graphic received by a comparator 5 is the sum between a voltage division of an output of a white noise generator 7 by a variable resistor 8 and an output of a CCD image sensor 3 by an adder 9 and the sum changes irregularly timewise with respect to the substantial output of the CCD image sensor 3. In comparing the output with a threshold voltage decided by a variable resistor 6, since the probability of the output with logical '1' of the comparator 5 is increased as the output of the adder 9 increases, that is, the output of the CCD image sensor 3 increases, the frequency of output being logical '1' is increased according to the density of the inputted graphic and the intermediate tone is expressed in a pseudo way. In this case, the variable resistor 6 adjusts the density and the variable resistor 8 adjusts the contrast.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] An image scanner device is shown in which a noise signal is added to an analog signal output from an optical reading section and then compared with a dark value voltage.

[Industrial application field]

The present invention relates to an image scanner device.

[Conventional technology]

Conventionally, when inputting a multivalued figure such as a photograph using an image scanner device, the figure was read as an analog signal, converted to a digital signal by an A/D converter, and then read into a computer.

FIG. 2 is a diagram showing an example of the configuration of a conventional image scanner device.

In FIG. 2, 1 is a control unit that controls the image scanner device, 2 is a timing generator, 3 is a CCD image sensor, and 4 is a synchronization signal destination main voice unit for synchronizing the image data signal with the host computer. , 5 is a comparator that outputs an image data signal, and 6 is a variable resistor that divides the reference voltage.

The operation shown in FIG. 2 will be explained. When the control unit 1 receives a reading command from the host computer, the control unit 1 instructs the timing generator 2 to generate timing, the CCD image sensor 3 to start reading, and the synchronization signal generator 4 to synchronize with the host computer. Instructs the generation of a signal. As a result, according to the timing generated by the timing generator 2, the CC of 3
The image sensor D generates a reading operation, and the synchronization signal generator No. 4 generates a synchronization signal. The output of the CCD image sensor 3 is compared with the dark value voltage determined by the variable resistor 6 by the comparator 5, and if it is higher than the dark value voltage, it is set as "1".
If it is smaller, "0" is output.

[Problem that the invention seeks to solve]

In order to reduce the amount of memory used, and because output devices such as printers are only capable of outputting binary values, the graphic data read in the above manner is often converted from multivalued data to binary data. was stored in memory. In this process, before the graphic data is converted into binary data, the multi-valued graphic data is read in, which temporarily requires a large amount of memory, which creates a problem in that a large amount of memory is required. .

[Means for solving problems]

Figure 1 shows the principle configuration of an image scanner device according to the present invention. In the figure, 20 is an optical reading section, 21 is a noise generation section, 22 is an addition section, 23 is a dark value voltage generation section, and 24 is a comparator. be.

The analog signal output from the optical reading section 20 that is compared with the dark value voltage is irregularly increased or decreased over time because noise from the noise generating section 21 is added thereto. The comparator 24 compares the analog signal output irregularized via the adder 22 and the dark value from the threshold voltage generator 23 .

Here, since the probability that the output of the comparator 24 becomes "1" increases according to the magnitude of the output of the optical reading section 20, the binary image scanner device is used as a device that can handle pseudo-multivalued data. be able to.

[Effect]

As mentioned above, the probability that the output of the comparator 24 becomes "1" increases as the output of the adding section 22 increases, that is, as the output of the optical reading section 20 increases, so the output increases according to the density of the input figure. The frequency of "1" increases, and pseudo-halftones can be expressed.

According to the present invention, an image scanner device can convert a multivalued figure into a binary figure without any need for a buffer memory for storing figure data or an expensive high-speed A/D converter, and furthermore, it is possible to convert a multilevel figure into a binary figure without requiring any buffer memory for storing figure data or an expensive high-speed A/D converter. It becomes possible to significantly reduce the amount of processing, the amount of data transferred to the host computer. Furthermore, weighting with respect to density can be easily performed, making it easy to correct COD characteristics, human preference, printer and display characteristics, etc. In addition, several types of weights can be easily switched by instructions from the user or the computer.
It becomes possible to assign weights that suit the purpose.

〔Example〕

FIG. 3 is a block diagram of the first embodiment of the present invention. Third
In the figure, the same numbers as those in FIG. 2 described above are the same, 7 is a white noise generator using an FM demodulation circuit, 8 is a variable resistor that divides the output of the white noise generator, and 9 is an adder. The analog signal indicating the density of the figure received by the comparator 5 is obtained by dividing the output of the white noise generator 7 with the variable resistor 8 and the output of the CCD image sensor 3 using the adder 9. This is the sum of the sums, which increases or decreases irregularly over time with respect to the original output of the CCD image sensor 3. However, when comparing this output with the dark value voltage determined by variable resistor 6, the output of comparator 5 is “
If the output of the adder 9 increases, the output of the CCD image sensor 3 increases as the size increases, so the output becomes ``1'' according to the density of the input figure.
The frequency of this increases, and it is possible to express halftones in a pseudo manner. In this example, the density can be adjusted using the 6 variable resistors, and the contrast can be adjusted using the 8 variable resistors.

FIG. 4 is a block diagram of a second embodiment of the present invention. Fourth
In the figure, the same numbers as in FIGS. 2 and 3 above are the same, 10 is a counter, 11 is a ROM, 12 is a D/A converter, and 13 is a launch.

In this case, the control unit 1 receives a read operation command from the host computer, and as a result, the synchronization signal generator 4 first sets an initial value in the counter 9 and starts the read operation. The counter 10 counts according to the output of the timing generator 2, and outputs the output to the address of the ROM 11. Then, the ROM 11 reads out the data corresponding to the address and outputs it to the D/A converter 12. This output is added to the output of the CCD image sensor No. 3 by an adder No. 9, and increases and decreases over time with respect to the original output of the CCD image sensor No. 3. In this case as well, the third
As in the case of the figure, when this output is compared with the reference voltage of the other input of the comparator 5, the probability that the output of the comparator 5 becomes "1" is that the output of the adder 9 becomes larger, that is, 3 Since the output of the CCD image sensor increases in accordance with the magnitude of the output, the output becomes "1" more frequently in accordance with the density of the input figure, and a pseudo halftone can be expressed. 4 sync signal generators 10 counters and 3 CCs
Each time one horizontal scan of the D image sensor is completed, a value different from the value set during the previous horizontal scan is set,
This is designed to take the original value at regular intervals,
It has regular data in the horizontal and vertical directions, that is, in the two-dimensional direction, according to the data in the ROM No. 11. In addition, random number data, data that repeats large and small values in two dimensions, data that is biased toward large values or small values are written in the ROM of 11, and any value can be sent from the host computer. Since the selection is made based on the output of the latch No. 13, the weights regarding shading can be easily changed by the host computer.

[Effects of the Invention] According to the present invention, an image scanner device that cannot express intermediate densities and handles only the presence or absence of black and white can be made into a device that can express pseudo multi-values by inexpensive means. The practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the principle configuration of the present invention. FIG. 2 is a diagram showing an example of the configuration of a conventional image scanner device. FIG. 3 is a diagram showing the configuration of the first embodiment of the present invention. FIG. 2 is a configuration diagram of a second embodiment. In the figure, 1 is a control unit, 2 is a timing generator, and 3 is a CCD.
Image sensor, 4 is a synchronizing signal generator, 5 is a comparator, 6 is a variable resistor, 7 is a white noise generator, 8 is a variable resistor, 9 is an adder, 10 is a counter, 11
is a ROM, 12 is a D/A converter, and 13 is a latch. Is the present invention the ΔX-diλ cana'X of the tree in the first part of Torito's figure 4? Presentation JJ'll 2nd Copy Book 1 Invention's 1st Kageki I/) Filled ζ7 3rd Σ

Claims (4)

[Claims] (1) Optical reading means (20) that reads a figure and outputs an analog signal according to its shading; Noise generating means (21); Output of the optical reading means (20); and Noise generating means (21) an adding means (22) for adding the outputs of the above-mentioned adding means (22); a threshold voltage generating means (23) for adding the outputs of the above-mentioned adding means (22);
An image scanner device characterized by comprising a comparator (24) that compares the output of 23) and converts the signal into a "1" or "0" signal and outputs the signal. (2) The image scanner device according to claim (1), wherein the noise generating means (21) is a white noise generator (7). (3) The noise generating means (21) is a counter (10)
, a memory (11) that inputs the output of the counter (10) as an address, and a D/A converter (12) that inputs the output of the memory (11). An image scanner device according to claim (1). (4) The memory (11) has more address signal lines than the output signals of the counter (10), and the noise generating means (21) fixes a part of the address signal lines to an arbitrary value. An image scanner device according to claim 3, characterized in that it comprises address fixing means (13).