JPH02266672A - Image pickup device - Google Patents

Abstract

PURPOSE:To constitute an in-field differentiating vertical aperture compensation circuit and an inter-field quadratic differentiating compensation circuit with less number of line memories than that of conventional circuits by using an output of the line memory storing an interpolation signal so as to apply vertical aperture compensation. CONSTITUTION:A vertical low pass filter(LPF) 24 uses a delay signal through line memories 20, 22 to form interpolation signal and the formed interpolation signal is stored in a line memory 26 for interpolation data. Since the line memory 26 for forming the interpolation signal is used for one line delay for vertical aperture compensation, the number of line memories in use is decreased. Thus, an in-field first order derivative vertical aperture compensation circuit and an inter-field second order derivative compensation circuit are constituted with less number of line memories than that of conventional circuits.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an imaging device using a solid-state imaging device in which a pixel array is arranged in a two-dimensional offset arrangement.

[Prior Art] Traditionally, imaging devices using solid-state imaging devices have been used for video and
Widely used in cameras, still video cameras, etc. Initially, the solid-state image sensors used in these applications were
A device with a photosensitive area in which square or rectangular photodetectors were regularly arranged in a matrix was used, but in recent years,
As the demand for improved image quality increased, the image quality of solid-state image sensors was improved, and as shown in Figure 2, each pixel (light receiving element) was made into a summer shape or hexagonal shape, and the center of gravity of each pixel was constructed with a two-dimensional offset structure. A solid-state image sensor has been developed. This pixel arrangement makes it possible to improve image quality while suppressing a reduction in light-receiving area (that is, a decrease in sensitivity).

However, in the image sensor shown in FIG. 2, if the signal is read out in a zigzag manner on a horizontal line to form a TV signal as shown by the arrow (solid line or broken line), moiré will occur, so non-sample points (for example, ○ or It is necessary to interpolate the signal of the mouth point) when ・ is the sample point, and furthermore, it is necessary to provide a two-dimensional filter with a huge signal processing section in order to limit the band in the horizontal direction. . Furthermore, the interpolation process requires a large number of line memories or frame memories.

[Problems to be Solved by the Invention] When attempting to perform vertical aperture compensation in the conventional example described above, a line memory for that purpose is required, and when the line memory for the above interpolation processing is added, a considerably large number of lalin memories are required. is required. When considering IC implementation, the necessity of such a large number of line memories is a problem.

Therefore, it is an object of the present invention to provide an imaging device that requires less line memory.

[Means for Solving the Problems] An imaging device according to the present invention includes an imaging device in which a photoelectric conversion element of a photosensitive portion is arranged two-dimensionally offset,
The signals of the photoelectric conversion elements in two adjacent rows of the photosensitive section are read out in a zigzag manner and temporarily stored in a memory means to form a predetermined interpolated signal. This imaging device is characterized in that it performs vertical aperture compensation using the output of a memory means that holds an interpolation signal.

[Operation] With the above means, the memory means for interpolation signals is also used for one line delay for vertical aperture compensation, so the number of memory means can be reduced accordingly.

That is, an intra-field-order differential vertical aperture compensation circuit and an inter-field second-order differential compensation circuit can be realized with fewer line memories than conventional ones.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram of an embodiment of the present invention. 1
0 is an image sensor in which the light-receiving element array of the photosensitive part has a two-dimensional offset structure as shown in FIG.
, B are output. It is assumed that the image sensor 10 includes 3n (n is a positive integer) light receiving elements in the horizontal direction and m (positive integer) light receiving elements in the vertical direction. Reference numeral 11 denotes a system signal generation circuit (SSG) that generates a system signal for synchronously operating each part of the circuit. switch 12
The three outputs of the image sensor 10 are sequentially selected in the order indicated by the arrows (solid or broken lines) in FIG. Hereinafter, such readout will be referred to as zigzag readout. The signal read out in a zigzag manner in this way is sampled and held in the sample/hold circuit 14.
The signal is held and digitized by the A/D converter 16. Note that gamma correction and white balance are performed at the same time in the A/D converter 16.

The digital signal from the A/D converter 16 is sent to the switch 1
8, the signal in the upper row of the photosensitive area is transferred to the line memory 2.
0 and the lower row signal is applied to line memory 22. Vertical low-pass filter (LPF) 24 uses the delayed signal from line memory 20.22 to
Form an interpolated signal. For example, in the case of the second field shown in FIG. 3, an interpolated signal △ is formed from the signal ◎ and the signal O, and thereby F2. Create Fl. The formed interpolated signal is stored in a line memory 26 for interpolated data.

Now, when the signal O is coming to the output of the switch 18, the signal ◎ still remains in the line memory 20 or 22. Therefore, if only half of the signal output of the signal synthesized by the vertical LPF 24 is stored when outputting F2, the vertical LPF
When F24 is F2°, F2 can be recombined, and by using these two signals, vertical aperture compensation can be performed between scanning lines within a field. That is, 36 is the vertical aperture compensation circuit.

The output of the vertical aperture compensation circuit 36 is a luminance signal LPF.
38. The LPF 38 is a FIR (Finite Impulse Response) type digital filter, which is subjected to horizontal band limitation and is connected to the D/A converter 40 and the LPF.
A luminance signal is output to the outside via 42.

Regarding color signal processing, the switch 32 extracts the signal that has not been subjected to vertical aperture compensation, and the signal is sent to the color signal processing circuit 4.
4 converts the RGB signal into a color difference signal RY.

The signal is converted to B-Y, and at the same time, the band is limited in the horizontal direction as well.

After this, similarly to the luminance signal, the D/A converter 46.47
and a color difference signal R-Y to the outside via LPF48.49.
Output B-Y.

The operation in the second field has been described with reference to FIG. 3. In the first field, zigzag reading is performed in the reverse order of the second field. The relationship between first field readout and vertical aperture compensation is shown in FIG.

FIG. 5 shows a block diagram of another embodiment of the present invention,
FIG. 6 shows the readout order of the first field and inter-field second-order differential aperture compensation.

The same components as in FIG. 1 are given the same reference numerals.

Reference numeral 5o designates a field-only image pickup device, 52 a system signal generation circuit, and 56 a line memory for storing interpolated data corresponding to the line memory 26 in FIG. line·
The operation up to allocation to the memories 20 and 22 is the same as in the case of FIG. As shown in Fig. 6, when creating the F1 signal, the F2' signal is set to a half
Since it can be created using a memory capacity, vertical second-order differential aperture compensation between fields can be performed by using the F2 signal that is created simultaneously with the F1 signal. The vertical aperture compensation circuit 56 in FIG. 5 performs vertical second-order differential aperture compensation.

Although the configuration shown in FIG. 5 is a field-only image pickup apparatus, vertical second-order differential aperture compensation can also be performed for the second field by performing upside-down zigzag reading as in the embodiment shown in FIG. Further, in the case where the image sensor 50 cannot perform zigzag readout or upside down zigzag readout, the output may be A/D converted and then stored in the frame memory. The present invention is not limited by the signal reading method.

[Effects of the Invention] As can be easily understood from the above explanation, according to the present invention, a vertical aperture compensation circuit can be realized with less memory means, the circuit size can be reduced, and power consumption and manufacturing cost can be reduced. can be achieved.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the configuration of an embodiment of the present invention, FIG. 2 is an explanatory diagram of the pixel arrangement of the photosensitive part of the image sensor, and FIG. 3 is an explanatory diagram of intra-field aperture compensation of the second field in FIG. , FIG. 4 is an explanatory diagram of intra-field aperture compensation of the first field, FIG. 5 is a block diagram of another embodiment of the present invention, and FIG. 6 is an illustration of the inter-field quadratic differential of the first field of FIG. FIG. 3 is an explanatory diagram of aperture compensation. 10.50: Image sensor 11, 52 System signal generation circuit 20, 22 Line memory 24: Vertical LPF
26, 56 + line memory for interpolated data 60:
Vertical aperture compensation circuit diagram

Claims (1)

[Claims] The photosensitive section is equipped with an image sensor in which the photoelectric conversion elements are two-dimensionally offset, and two adjacent photoelectric conversion elements of the photosensitive section are provided.
The imaging apparatus reads signals from photoelectric conversion elements in a row in a zigzag manner, temporarily stores them in a memory means to form a predetermined interpolated signal, and makes the vertical order of the zigzag readout different between the first field and the second field. , an imaging apparatus characterized in that vertical aperture compensation is performed using an output of a memory means holding an interpolation signal.