JPH044478A - Image processing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an image processing device that processes an output signal of a CCD line image sensor by analog-to-digital (A/D) conversion, and particularly relates to an image processing device that performs shape ink correction. It is related to.

[Prior Art] FIG. 6 is a block diagram showing a schematic configuration of the main parts of a conventional image processing device.

In FIG. 6, a clock generation circuit 2 drives a CCD line image sensor 1 to obtain an output signal. At this time, it is assumed that no object is projected within the field of view of the CCD line image sensor 1 and that the output signal is not saturated.

Therefore, the output signal of the CCD line image sensor 1 is A.
A/D converter 3 performs A/D conversion for each pixel. This A/D converted digital signal for each pixel is written into a RAM table 4 which is a memory by an address counter 5. In this way, the first line of data is written to the ram table 4 and stored. The stored data of the Ramcheezle 4 is read out pixel by pixel in synchronization with the next output signal of the CCD line image sensor 1 and inputted to the integrator 6. Therefore, the output signal of the CCD line image sensor is input to the A input terminal of the integrator 6, and the data of the ram table 4 is input to the B input terminal.

Next, the integrator 6 calculates AXB to correct unevenness in light amount and sensitivity.

[Problem to be solved by the invention] In the conventional apparatus as described above, a digital integrator must be constructed in order to correct shape ink such as uneven light amount and uneven sensitivity, and the configuration of the integrator is However, it is more complex than an analog integrator, and the number of parts in the entire circuit is large.

Also, since a digital integrator is used, there is a problem that it becomes inaccurate when the signal is dark (low level).

The present invention has been made to solve the above problems, and an object of the present invention is to provide an image processing device that can obtain an accurate signal with shading corrected using a device with a simple configuration.

[Means for Solving the Problems] In order to achieve the above object, the image processing device of the present invention, in claim (1), converts the output signal of the CCD line image sensor into a digital signal using an analog-to-digital converter. In an image processing apparatus that converts C into C and processes this converted digital signal, C
A signal for the first line of the CD line image sensor is stored in a memory, this stored signal is converted by a digital-to-analog converter, and this converted analog signal is used as a reference signal for the analog-to-digital converter. Further, the signal from the next line of the CCD line image sensor is converted from analog to digital based on the reference signal to obtain a digital signal.
In 2), the signal for one line of the CCD line image sensor and the output signal of the CCD line image sensor are converted into digital signals by an analog-to-digital converter, and the image processing device processes the converted digital signals. , among the digital signals, the signal for the first line of the CCD line image sensor is stored in a memory, this stored signal is converted by a digital-to-analog converter, and the converted analog signal and the CCD line image sensor are converted. The signals from the next line onwards are input to an integrator and integrated, and the output of this integrator is converted into a digital signal.

[Function] Each of the inventions described above allows the device to be made smaller and to accurately process even dark signals.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of the main parts of an embodiment of an image processing apparatus according to the present invention.

In FIG. 1, the clock generation circuit 2 generates a CCD
The line image sensor l is driven to obtain an output signal.

At this time, assuming that no object is projected within the field of view of the CCD line image sensor and that the output signal is not saturated, the output signal will be as shown in FIG. 3.

The output signal of this CCD line image sensor 1 is A/D converted by an A/D converter 7 pixel by pixel. The A/D converted digital signal for each pixel is written into the ram table 4 by the address counter 5. In this way, the CCD
Data for one line of the line image sensor 1 is written to the ram table 4 and stored. At this time, the signal stored in the ram table 4 is a signal with uneven light amount and uneven sensitivity.

Then, the next output CCD line image sensor l
The address counter 5 reads out the data stored in the laminate full 4 pixel by pixel in synchronization with the output signal (FIG. 4(b)), and the read data is subjected to digital-to-analog (D/A) conversion. The signal is D/A converted by the converter 8 (FIG. 4(a)), and is input to the reference input terminal (Vref) of the A/D converter 7.

The A/D converter 7 reads out the ram table 4 and outputs the D
Using the /A converted signal as a reference signal, the output signals of the second line and subsequent lines of the CCD line image sensor 1 are converted into digital signals based on this reference signal.

By doing this, the output signal of the CCD line image sensor 1 is weighted for each pixel during A/D conversion, and A/D conversion is performed without unevenness in light amount or CCD sensitivity. The resulting data is obtained as a shaped waveform as shown in FIG. 4(C).

FIG. 2 illustrates the above operation of FIG. 1 using a timing chart, and FIG. (b) is a waveform diagram of the data written in the ram table 4 from the signal for the first line when nothing is projected on the CCD line image sensor 1 in (a) of the same figure. (C) is output from ram table 4 (
FIG. 3 is a waveform diagram showing data to be read out.

Furthermore, FIG. 5 is a block diagram showing a schematic configuration of the main parts of another embodiment of the present invention.

In the embodiment described above, the data of the ram table was converted into digital data and inputted to the Vref input terminal of the A/D converter, or in the embodiment shown in FIG. After integrating the output of the CCD line image sensor and the data of the ram table using the integrator, the A/
This is the input to the D converter.

The operation of this embodiment will be explained below with reference to FIG.

In FIG. 5, a clock generation circuit 2 drives a CCD line image sensor to obtain an output signal. At this time, it is assumed that no object is projected within the field of view of the CCD line image sensor and that the output signal is not saturated.

The output signal of the CCD line image sensor is input to the input terminal of an analog integrator 9. At this time, 1 is input to the B input terminal.

The AXB output of the integrator 9 is CCed by the A/D converter 3.
A/D conversion is performed for each pixel of the D line image sensor.

This A/D converted digital signal for each pixel is written into the ram table 4 by the address counter 5. In this way, data for one line of the CCD line image sensor is written and stored in the ram table 4. The data stored in this RAM table 4 is then output to the CCD.
The data is read out pixel by pixel in synchronization with the output signal of the line image sensor, and the data is converted to D/A by the D/A converter 8.
A convert. This D/A converted output signal is input to the B input terminal of the integrator 9.

Then, the output signal of the CCD line image sensor 1 input to the input terminal of the integrator 9 and the signal input to the B input terminal are integrated by the integrator 9 for each pixel.

As a result, the integrator 9 outputs a signal with no unevenness in sensitivity or light intensity of the CCD line image sensor, and this signal can be A/D converted by the A/D converter 3.

Some A/D converters have circuit configurations that cannot be used as in the embodiment shown in Fig. 1, but the embodiment shown in Fig. 5 A converter may also be used.

As described in 2 below, the digital data obtained by converting the output signal of the CCD line image sensor obtained in each embodiment can be inputted to, for example, an edge detector or the like to detect the edges of an object. It is possible to perform accurate measurements without errors.

[Effect of the invention] As explained above, according to claim (1) of this invention,
The device is small and the number of parts can be reduced, and also in claim (2), there is no need to use a digital integrator, so the number of parts is small, and the integration is performed in an analog section provided at the previous stage. Therefore, even signals that are somewhat dark are accurate.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing a schematic configuration of the main parts of an embodiment of an image processing apparatus according to the present invention, and FIG. 2 is a timing chart for explaining the operation of FIG.
a) is the A/D output signal of the CCD line image sensor
A waveform diagram of the converted data, Figure (b) is a waveform diagram of one line of data in Figure (a) written in the ram table,
Figure 4 (C) is a waveform diagram of the data read from the RAM table, Figure 3 is a waveform diagram of the output signal of the CCD line image sensor in Figure 1, and Figure 4 (a) is the A/D diagram in Figure 1. Waveform diagram of the signal input to the Vref input terminal of the converter, same figure (b
) is a waveform diagram of the output signal of the CCD line image sensor after the second line, (C) is a waveform diagram of the output signal of the A/D converter of FIG. 1, and FIG. 5 is a waveform diagram of the output signal of the A/D converter of FIG. 1. FIG. 6 is a block diagram showing a schematic configuration of the main parts of a conventional image processing apparatus. In the figure, 1: CCD line image sensor 2: Clock generation circuit 3.7. : A/D converter 4 Niramuchiful 5 Near address counter 8 : D/A converter 9: Analog integrator Agent Patent attorney 1) Haru Kitatake Procedural amendment (method) Figure 4

Claims (2)

[Claims] (1) In an image processing device that converts an output signal of a CCD line image sensor into a digital signal by an analog-to-digital converter and processes this converted digital signal, the first one of the digital signals of the CCD line image sensor A line worth of signals is stored in a memory, this stored signal is converted by a digital-to-analog converter, the converted analog signal is used as a reference signal for the analog-to-digital converter, and further, the CCD line image sensor is An image processing apparatus characterized in that a signal after the next line is converted from analog to digital based on the reference signal to obtain a digital signal. (2) In an image processing device that converts an output signal of a CCD line image sensor into a digital signal by an analog-to-digital converter and processes the converted digital signal, the first one of the digital signals of the CCD line image sensor A line worth of signals is stored in a memory, this stored signal is converted by a digital-to-analog converter, and this converted analog signal and the signal from the next line of the CCD line image sensor are input to an integrator. An image processing device characterized in that the output of the integrator is converted into a digital signal.