JP6534824B2 - Imaging device and control method of imaging device - Google Patents

Description

  The present invention relates to an imaging device.

A general color imaging device is sensitive to noise, signal-to-noise (S / N ratio), color, etc., due to temperature changes of an imaging device such as a charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS) Characteristics change.
As a prior art document, for example, in Patent Document 1, in an image pickup apparatus having an area sensor including a plurality of photoelectric conversion elements arranged in two dimensions, a photographing output at the time of photographing exposure from a gain adjustment circuit connected with the area sensor A frame memory for storing, a condition memory circuit for storing shooting conditions at the time of shooting exposure, an AE controller for obtaining a correction output using the stored shooting conditions, and a correction output from a gain adjustment circuit controlled by the AE controller And an arithmetic processing circuit that corrects the imaging output using the

Japanese Patent Application Publication No. 2003-244557 JP, 2013-118503, A JP, 2009-246441, A Patent No. 2995683 Patent No. 3456818 gazette JP-A-55-58688

In an imaging device used for determining the ripeness of fruits by color, it is strictly required that the hue of the video signal does not fluctuate due to the outside air temperature and the internal temperature of the imaging device. If it is the temperature characteristic for each color channel, it may be compensated for each channel, but it is easy to compensate for the change of the transmission characteristic of the color filter and other optical elements and the change of the spectral sensitivity characteristic of the image sensor. is not. That is, since it is not possible to uniquely determine the optimum correction for any image, it has to be adjusted by a skilled engineer in an actual object and lighting environment.
An object of the present invention is to perform correction corresponding to the temperature around the imaging device and the temperature around the signal processing unit.

  The imaging apparatus according to the present invention includes an imaging device, a signal processing unit, a control unit, a memory unit, and a temperature detection unit. The temperature detection unit detects the temperature around the imaging device, and the memory unit compensates for the temperature characteristics of the imaging device. The controller has a value table, and the controller reads out the compensation value for the temperature detected by the temperature detector from the memory and controls the signal processor.

  Further, the imaging device of the present invention includes an imaging element, a signal processing unit, a control unit, a memory unit, and a temperature detection unit, the temperature detection unit detects the temperature around the signal processing unit, and the memory unit is a signal processing unit. The controller has a compensation value table for the temperature characteristic of the output signal, and the controller reads the compensation value for the temperature detected by the temperature detector from the memory and controls the signal processor.

  Furthermore, the imaging device of the present invention includes an imaging element, a signal processing unit, a control unit, a memory unit, a first temperature detection unit, and a second temperature detection unit, and the first temperature detection unit is The second temperature detection unit detects the temperature around the signal processing unit, and the memory unit detects the compensation value table for the temperature characteristic of the imaging device and the compensation value table for the temperature characteristic of the output signal of the signal processing unit. And the control unit controls the signal processing unit by reading from the memory unit the compensation value for the temperature detected by the first temperature detection unit and the compensation value for the temperature detected by the second temperature detection unit. I assume.

According to the present invention, it is possible to perform correction corresponding to the temperature around the imaging device and the temperature around the signal processing unit .

It is a block diagram for explaining an imaging device concerning one embodiment of the present invention. It is a block diagram for demonstrating the imaging device which concerns on other one Embodiment of this invention. It is a block diagram for demonstrating the imaging device which concerns on other one Embodiment of this invention. It is a figure for demonstrating the compensation value table memorize | stored in the memory part of the imaging device concerning one Embodiment of this invention. It is a figure for demonstrating the means for producing | generating the compensation value of the imaging device which concerns on one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Example 1
One embodiment of the present invention will be described with reference to FIGS. 1, 4 and 5. FIG.
FIG. 1 is a block diagram of an imaging apparatus according to a first embodiment.
In FIG. 1, the imaging apparatus 100 includes an imaging unit 101, a signal processing unit 104, a video signal output unit 107, a control unit 108, and a memory unit 109.
The imaging unit 101 includes an imaging element 102 and a temperature detection unit 103.
The imaging device 102 may be a single plate or a plurality of plates such as three plates.
The video signal processing unit 105 of the signal processing unit 104 may be configured by an FPGA (Field Programmable Gate Array) or the like.
The temperature detection unit 103 detects (measures) the temperature around the imaging element 102, and detects the temperature using a PN junction diode, a temperature measuring resistor, a thermistor, a thermocouple, or the like. It is desirable that the temperature detection unit 103 be provided inside the imaging device 102 if the imaging device 102 is a single plate, and be provided at a temperature close to the temperature of the prism (dichroic mirror) if three.

The imaging element 102 outputs a video signal obtained by photoelectrically converting incident light (not shown) to the video signal processing unit 105 of the signal processing unit 104.
The video signal processing unit 105 performs level adjustment, white balance adjustment, color tone correction, contour correction, gamma correction, knee correction, shading correction, and the like on the video signal output from the imaging device 102, and the video signal output unit 107 Output.
The video signal output unit 107 outputs the video signal output from the video signal processing unit 105 as, for example, an SDI (Serial Digital Interface) signal, a USB3 Vision (trademark) signal, or a GigE Vision (trademark) signal. The video signal output unit 107 may compress or encrypt the video signal and output it.
The control unit 108 is, for example, a CPU (Central Processing Unit) or the like, and controls the entire imaging apparatus 100.

The memory unit 109 stores, for example, a compensation value for the temperature characteristic of the image sensor 102.
The compensation value or the like for each temperature stored in the memory unit 109 is one that is individually acquired in advance, or one that is generated by evaluating fluctuation characteristics acquired from a plurality of imaging devices 100. As an example, a color chart (Munsell color sample) is photographed under industrial light of natural light (AM 1.5) or high color rendering (Ra> 95), assuming an actual use environment of an imaging device as an example. Do.
The control unit 108 always reads the temperature value of the temperature detection unit 103, reads the compensation value for the temperature from the compensation value table stored in the memory unit 109, and corrects the hue and the like.

FIG. 4 is a diagram for explaining the compensation value table stored in the memory unit of the imaging apparatus of the first embodiment.
The compensation value table of FIG. 4 is a compensation value of a hue corresponding to a temperature of −10 ° C. or less to 100 ° C. or more based on 25 ° C.
The hue compensation values in FIG. 4 are six colors of Red, Green, Blue, Cyan, Magenta and Yellow, but can be applied to 12 colors or linear correction.

  When the temperature is not in the compensation value table, for example, the control unit 108 reads out the two compensation values closest to the corresponding temperature from the memory unit 109, linearly interpolates the two read out compensation values, and generates a compensation value. Do.

FIG. 5 is a diagram for explaining means for generating the compensation value of the imaging device of the first embodiment.
FIG. 5 is a diagram in which the video signal output of the imaging device 100 is displayed on a vector scope. The vectorscope traditionally uses chrominance (Cb = BY and Cr = RY) on the horizontal and vertical axes, but here it is assumed that the radial direction is saturation from the origin and the circumferential direction is hue. The hue compensation values of six colors are generated for each temperature of a predetermined interval (for example, 10 ° C.) using a vector scope.

In the case of Red on the vector scope, the imaging device 100 adjusts the saturation to 127 (variable range 0 to 255) when the temperature detected by the temperature detection unit 103 is 25 ° C., and the hue 127 (variable range 0 to 0). Adjust to 255).
For example, when the control unit 108 reads the temperature value 0 ° C. detected by the temperature detection unit 103, the compensation value of Red in FIG. 4 is 0.03, so 127 × 0.03 ≒ 4 is obtained for 127 of the hue. Add and compensate the hue to 131.
Note that the hue compensation values for multiple colors such as 12 colors and linear are displayed using a display device that can display HSV (Hue, Saturation, Chroma, Value, Lightness, Brightness) color space, etc. It may be generated every temperature of a predetermined interval (for example, 5 ° C.).

FIG. 2 is a block diagram of a color correction circuit included in the video signal processing unit 105 of the imaging apparatus of the first embodiment.
The color correction circuit shown in FIG. 2 is a so-called six-color independent masking disclosed in Patent Document 4. The HSV color space comprises red, yellow, green, cyan, cyan and blue magenta and magenta colors based on hue. It is divided into six areas, and the hue and saturation can be adjusted independently for each area. In most cases, the region is determined by the maximum value among six colors, or by the combination of the signs of three difference signals such as RB, and the correction value is generated from these difference signals.

Specifically, in the color correction circuit of Patent Document 4 used in this example, correction is performed as follows.

Here, K4 to K6 and K10 to K12 are coefficients related to hue, and a value obtained by adding a user setting value (if any) to the compensation value of the compensation value table of FIG. 4 is set. K1 to K3 and K7 to K9 are mainly coefficients relating to saturation, and are not essential in this example, and for example, user setting values (if any) are set as they are.
The correction becomes 0 on the boundary and linearly increases toward the inside of the area, and it is difficult to correct the color near the boundary with the color correction circuit of FIG. 2 alone. In such a case, another system of six color correction circuits having different boundary positions as in Patent Documents 5 and 6 may be provided.

(Example 2)
Another embodiment of the present invention will be described with reference to FIG.
FIG. 3 is a block diagram for explaining an imaging apparatus according to a second embodiment of the present invention.
A difference from FIG. 1 is that two temperature detection units are provided in the imaging unit.
In FIG. 3, the imaging device 300 includes an imaging unit 101, a signal processing unit 204, a video signal output unit 107, a control unit 308, and a memory unit 309.
The imaging unit 101 includes an imaging element 102 and a temperature detection unit 103.
The temperature detection unit 103 detects the temperature of the periphery (prism or other optical element) of the imaging device 102 .
The signal processing unit 204 includes a video signal processing unit 105 and a temperature detection unit 206.
The temperature detection unit 206 detects the temperature around the video signal processing unit 105 .

The imaging element 102 outputs a video signal obtained by photoelectric conversion of incident light (not shown) to the video signal processing unit 105 of the signal processing unit 204.
The video signal processing unit 105 performs level adjustment, white balance adjustment, color tone correction, contour correction, gamma correction, knee correction, shading correction, and the like on the video signal output from the imaging device 102, and the video signal output unit 107 Output.
The video signal output unit 107 converts the video signal output from the video signal processing unit 105 into, for example, an SDI signal or a signal that can be distributed to a network, and outputs the signal.
The control unit 308 is, for example, a CPU or the like, and controls the entire imaging device 300.

The memory unit 309 is a correction value for the temperature dependence of wavelength dependency (spectral sensitivity characteristic) of the quantum efficiency of the silicon photodiode constituting the imaging element 102, and the temperature characteristic (if any) of the on-chip color filter of the imaging element 102. The correction value for the optical temperature characteristic of the imaging unit 101 and the like are stored as a correction value table for the temperature characteristic of the imaging device .
Furthermore, the memory unit 309 stores a correction value table for the temperature characteristic of the output signal of the video signal processing unit 105.
The correction value for each temperature stored in the memory unit 309 is generated by evaluating the fluctuation characteristic acquired individually or in advance acquired from the plurality of imaging devices 300.
The control unit 308 constantly reads the temperature values of the temperature detection unit 103 and the temperature detection unit 206, reads the correction value for the temperature from the correction value table stored in the memory unit 309, and adds the correction values. The hue etc. is corrected by applying to a color correction circuit as shown in FIG.
The control unit 308 corrects both the variation due to the temperature characteristic of the imaging device 102 and the variation due to the temperature characteristic of the video signal processing unit 105 by constantly reading the temperature value detected by the temperature detection unit 103 and the temperature detection unit 206. Can.

  The imaging apparatus according to the embodiment of the present invention can output a good video signal by performing correction corresponding to the external temperature and the internal temperature.

Although the present invention has been described in detail above, it is needless to say that the present invention is not limited to the imaging device described herein, and can be widely applied to imaging devices other than the above.
In the embodiment described above, the hue correction corresponding to the detected temperature is described as an example. However, the present invention is not limited to this, and can be applied to items having temperature fluctuations.

  100, 200, 300: imaging device, 101, 201: imaging unit, 102: imaging device, 103, 206: temperature detection unit, 104, 204: signal processing unit, 105: video signal processing unit, 107: video signal output unit , 108, 208, 308: control unit, 109, 209, 309: memory unit.

Claims (3)

The imaging device, the signal processing unit, the control unit, the memory unit, the first temperature detection unit, and the second temperature detection unit;
The first temperature detection unit detects a temperature around the imaging device,
The second temperature detection unit detects a temperature around the signal processing unit,
The memory unit includes a correction value table for temperature characteristics of the imaging device, and a correction value table for temperature characteristics of an output signal of the signal processing unit.
Wherein the control unit includes a correction value for the first temperature at which the temperature detecting section detects, by adding the correction value is read out from the memory portion to said second temperature at which the temperature detecting section detects the correction after addition An image pickup apparatus characterized by correcting processing of a video signal in the signal processing unit according to a value .   In the imaging device according to claim 1,
  The memory unit has a correction value table of hue to temperature characteristics of the image pickup device, and a correction value table of hue to temperature characteristics of an output signal of the signal processing unit.
  The control unit reads out from the memory unit the correction value of the hue to the temperature detected by the first temperature detection unit and the correction value of the hue to the temperature detected by the second temperature detection unit, and adds them. The hue of the video signal in the signal processing unit is corrected by the correction value of the hue after the addition
  An imaging device characterized by   A control method of an imaging apparatus including an imaging element, a signal processing unit, a memory unit, a first temperature detection unit, and a second temperature detection unit.
  The first temperature detection unit detects a temperature around the imaging element,
  The second temperature detection unit detects a temperature around the signal processing unit;
  The temperature detected by the first temperature detection unit with reference to the correction value table for the temperature characteristics of the image sensor stored in the memory unit and the correction value table for the temperature characteristics of the output signal of the signal processing unit And the correction value for the temperature detected by the second temperature detection unit are read out and added, and the processing of the video signal in the signal processing unit is corrected with the correction value after the addition.
  And controlling the imaging device.

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