JPH0341877A - High quality picture input device - Google Patents

Abstract

PURPOSE:To reduce the time for edge emphasis by emphasizing the edge of a read picture with a signal of a picture being out of focus and a focused pic ture signal arranged to image forming position. CONSTITUTION:Signals from a photodetector arrays 11, 12 are extracted in parallel and inputted to amplifiers A1, A2. A delay time of a delay circuit T is set to a time from the read of an image of a position on an original by the photodetector 11 till the photodetector 12 reads the image on the same position and the time is made identical to a read time of one line. Thus, a focused picture signal on the same position on an original and a picture signal being out of focus are simultaneously inputted 10 an adder 20. Thus, an output signal of the adder 20 is a picture signal subject to edge emphasis.

Description

TECHNICAL FIELD The present invention relates to a high-quality image input device that projects and reads a document onto a line sensor using a lens.

(Prior Art) Conventionally, an image processing technique called neighborhood processing has been used to emphasize the edges of an image read by a line sensor. This neighborhood processing will be explained with reference to FIG.

Main scanning direction (left/right direction) just read by the line sensor
Assuming that the image signal (referred to as can be subtracted from the original image signal f(x). 2 of f (x) at a certain point
To take the floor differential, the center pixel should be weighted 1 and the pixels on its left and right should be weighted -172, as shown in FIG.
Multiply by , and add this to the signal of the center pixel.

The signal obtained by second-order differentiation of f(x) is as shown in FIG. 5(c). This signal is 2 of f (X)
Since the differential has already been multiplied by -1, if it is directly added to the original signal, a signal as shown in FIG. 5(d) will be obtained, allowing edge enhancement processing.

For the sake of simplicity, we have explained edge enhancement processing only in the left and right directions, but in order to perform it two-dimensionally, see Figure 5(e).
As shown in , the surrounding four pixels including the sub-scanning direction (called the vertical direction) are 1/A (A>4).

The center pixel may be weighted as 1.

The above explained edge enhancement using neighborhood processing, but in order to perform neighborhood processing on images read by a line sensor, it is necessary to simultaneously capture and process signals from pixels on the top, bottom, left, and right of a certain pixel. . Line sensors can only read signals one line at a time, so they cannot process the signals of three pixels across the top and bottom at the same time. Therefore, after A/D converting the image signal of one screen, it is stored in the frame memory of the computer. A computer is used for this arithmetic processing, in which data is taken in, sequentially read from the frame memory, and arithmetic is performed by the above-mentioned neighborhood processing.

(Problems to be Solved by the Invention) The conventional means described above has the following problems. First, a large capacity memory is required to temporarily store one entire screen in the memory. The amount of information on one screen read by the line sensor is 1
This is an extremely large amount of 0' to 10' bits. The capacity of frame memory for images currently available in the market is at most ~10
'bit, and therefore it is necessary to arrange a large number of ordinary frame memories, which increases the cost of the device.

The second problem is that a computer of PC class or higher is required for arithmetic processing.

This also increases the price of the entire device.

A third problem is that the processing time becomes long because a huge amount of data for one screen is taken out from the memory and processed one after another.

(Object of the Invention) In view of the above-mentioned conventional problems, an object of the present invention is to provide a high-quality image input device that can perform edge enhancement in a short time using an inexpensive and simple circuit.

(Means for Solving the Problems) In order to solve the problems of the conventional method and achieve the object of the present invention, in the high-quality image input device of the present invention, the light receiving element rows of the line sensor are arranged in multiple rows. By arranging at least one light-receiving element row among the plurality of rows at a position shifted from the imaging position by the lens, the signal from the light-receiving element row (L2) is made into a signal of an out-of-focus image. Then, the signal obtained by dividing this signal by an appropriate value A is set to 81.

On the other hand, the in-focus image signal from the light-receiving element array (LL) placed at the imaging position is multiplied by a constant (11/A) and delayed by an appropriate time t, and this image signal is
shall be.

In the high quality image input device of the present invention, the output signal is 82-S.
Set to 1. Here, the delay time t is defined as the time from when Ll finishes reading a certain line until when L2 finishes reading the next line.

(Function) The function of the above means will be explained using FIG. In FIG. 4, numeral 3 is a document, and numerals 11 and 12 are light receiving element arrays. In FIG. 4, there are two light receiving element rows for simplicity. Assume that the light-receiving element array 11 arranged at the imaging position is now reading an image signal at a position P. The image captured by the light-receiving element array 11 is a sharp, focused image signal as shown in FIG. 4(b).

Next, after time T, the light-receiving element array 12 arranged at a position away from the imaging position reads the image signal at position P. Since the light-receiving element array 12 is arranged at a position away from the image forming position, the image signal read by it becomes an out-of-focus image signal as shown in FIG. 4(c).

Figure 4(d) shows the signal shown in (b) as a constant (1+1/A)
(Sl), and FIG. 4(e) is the signal shown in (c) divided by the value A (Sl).

FIG. 4(f) is the signal obtained by subtracting 81 from Sl.

In the signal shown in (f), the signal strength at the flat part is (b
) is the same as the original signal shown in (s), but the effect of the shaded area shown in (s) appears around the edges, and is larger on the Hi level side compared to the flat area, while on the Low level side the effect is larger than the flat area. become smaller.

In other words, an edge-enhanced signal is obtained.

The strength of edge enhancement can be varied by changing the value of A. Furthermore, since the image read by the light-receiving element array 12 is a two-dimensional blurred image, two-dimensional edge enhancement processing is possible in the present invention.

(Embodiment) Figure ↓ shows a configuration diagram of a first embodiment of the present invention, and a sectional view of the sensor section 1 is shown. In addition, in Fig. 1, 2 is an optical system, 3 is a document, 11 and 12 are the light receiving element rows shown in Fig. 4, 13 is a substrate, 14 is a protective film, and 15 is an n-10
There are 0 flat glass windows.

In FIG. 1, electrodes, wiring, etc. are omitted, and in this embodiment, there are two rows of light receiving elements. The optical system uses a rod lens that forms a 1-magnification image on the sensor. The light-receiving element array 11 is arranged at the image-forming position of the original image formed by the rod lens.

Therefore, the image signal read by the light-receiving element array 11 is a signal of a sharp, in-focus original image.

On the other hand, the light-receiving element array 12 is arranged on the same plane as the light-receiving element array 11, but there is a thin plate glass 100μ thick above it.
5 is installed, the optical distance from the rod lens 2 to the light-receiving element array 12 is longer than that of the light-receiving element array 11, and therefore the image signal read by the light-receiving element array 12 is a signal of an out-of-focus original image. becomes.

FIG. 2 shows an equivalent circuit of the embodiment shown in FIG. 1. In this embodiment, a matrix driving method was used as the scanning method. In FIG. 2, E is the power supply voltage, □ to 2 are common electrode switches, S11 to S1. and S21 to 82111 are individual electrode switches, A1 and A2 each have an amplification factor of (1
+1/A) and 1/A amplifier, T is delay circuit, 20
is an adder, and 21 is a light receiving element.

Signals from the light-receiving element array 11 and the light-receiving element array 12 are taken out in parallel and input to amplifiers At and A2, respectively. The delay time of the delay circuit T is set to the time from when the light-receiving element array 11 reads an image at a certain position on the document until the next time when the light-receiving element array 12 reads an image at the same position. Same as reading time. Therefore, the in-focus image signal and the out-of-focus image signal from the same position on the document are simultaneously input to the adder 20. As is clear from the principle of the present invention described above, the output signal of the adder is an edge-enhanced image signal.

Figure 3 shows a configuration diagram of the second embodiment of the present invention.The difference from the first embodiment is that there is a 100 step difference 16 between the light receiving element array 11 and the light receiving element array 12. has been established. The position of the light-receiving element array 11 was then set as the imaging position of the document image by the rod lens of the optical system 2. Therefore, the position of the light receiving element array 12 is shifted from the imaging position due to the step 16. Therefore, the image signal read by the light-receiving element array 11 is a signal of a sharp, in-focus original image, while the image signal read by the light-receiving element array 12 is a signal of an out-of-focus original image.

In this embodiment as well, the matrix drive method is used as the scanning method, and the circuit from each light receiving element array to the adder is the same as the circuit used in the first embodiment shown in FIG. An image signal with edge enhancement is obtained.

Only two embodiments of the present invention have been described above, and it goes without saying that various changes can be made without departing from the spirit of the present invention. for example.

In the first and second embodiments, if red, green, and blue filters are arranged on each light receiving element in an appropriate order, it can be used as an image input device for color originals.

In addition, instead of placing a filter on the light receiving element, striped red, green, and blue filters are placed between the rod lens and the sensor section, and even when reading images while replacing these three types of filters in sequence, the color remains unchanged. Images can be input.

Furthermore, a color image can be similarly input by using a method of sequentially switching three types of light sources: red, green, and blue. Furthermore, although the matrix driving method was used as the scanning method in this embodiment, it is clear that the present invention can be practiced regardless of the driving method or the type of sensor.

(Effects of the Invention) As described above, the present invention does not require arithmetic processing by a computer, and the memory capacity required for processing can be reduced by about three orders of magnitude compared to conventional means.

Therefore, the cost of the device can be significantly reduced. Furthermore, since processing only requires signal amplification and addition, two-dimensional edge enhancement can be instantaneously achieved. Furthermore, the degree of edge enhancement can be easily changed by adjusting the gain of the amplifier.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of the first embodiment of the present invention, and FIG. 2 is a configuration diagram of the first embodiment of the present invention.
3 is a block diagram of the second embodiment of the present invention, FIG. 4 is a diagram illustrating the present invention in detail, and FIG. 5 is a diagram showing the equivalent circuit of the embodiment shown in the figure. FIG. 4 is an explanatory diagram of edge enhancement processing using neighborhood processing. 1...Sensor section, 2...Optical system, 3...Original, 11.12...Light receiving element array, 13...Substrate, 14...Protective film, 15...Thin glass, 16...
・Step, 20... Adder, 21... Light receiving element,
E...Electrical g voltage, K, ... - common electrode switch, S11~S1□S21~S2. ...Individual electrode switch, A1...Amplifier with amplification factor of (1+1/A). A2...Amplifier with an amplification factor of 1/A, T...Delay circuit.

Claims (1)

[Claims] In an image input device that projects and reads an original on a line sensor with a lens, the line sensor has a plurality of light-receiving element rows arranged, and at least one light-receiving element row among the plurality of rows is imaged by the lens. By arranging them at different positions, the signal from the light-receiving element array becomes an out-of-focus image signal, and this signal and the focused image signal from the other light-receiving element array arranged at the imaging position are used for reading. A high-quality image input device characterized by emphasizing edges, etc. of an image.