JP3500018B2 - Focus adjustment method for TV door phone - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a focus adjusting method for a TV intercom apparatus comprising a slave unit with a camera and a master unit with a TV monitor connected to the slave unit with the camera by a transmission line.

[0002]

2. Description of the Related Art A conventional camera-equipped cordless handset of a door intercom device is generally provided with a plurality of semiconductor infrared light emitting elements (hereinafter, referred to as infrared LEDs) in order to secure photographing at night. I used it to project a video at night.

Further, as a focus adjusting method for a TV intercom apparatus, that is, a focus adjusting method for a slave unit with a camera, a black and white fringe chart is imaged and the level of a video (luminance) signal corresponding to the fringe portion of the fringe chart is adjusted. The focus was adjusted by moving the position of the lens mounted on the camera back and forth so as to obtain the peak value.

In addition, an incandescent lamp,
Illuminate the fringe chart using a fluorescent lamp or infrared LED light to increase the level of the corresponding video (luminance) signal, thereby making it easier to find the position where the peak value is obtained. I was adjusting the focus of the handset.

[0005]

In the above-mentioned conventional focus adjusting method for a TV intercom apparatus, an incandescent lamp, a fluorescent lamp, or an infrared LED light is used as illumination at the time of capturing the black and white stripe chart, and its spectral emission characteristic Due to the difference, when the adjustment is performed under the infrared LED light source, the image becomes clear under the infrared LED light source, but becomes blurry under the fluorescent light source, and conversely the adjustment is performed under the fluorescent light source. When
The image is clear under the fluorescent light source, but the infrared LED
There was a drawback that the image became blurry under the light source.

This is because the peak wavelength is different in the spectral characteristic (shown in FIG. 10) obtained by multiplying the spectral emission characteristic of each light source and the spectral sensitivity characteristic of the image sensor (CCD).
In particular, in the case of a lens with large chromatic aberration such as a plastic lens (a lens with a large change in the just focus position due to the difference in the wavelength of incident light), it was remarkable.

Further, as can be seen from the spectral characteristics shown in FIG. 10, particularly when the adjustment is performed under the light source of the incandescent lamp, the wavelength vs. spectral output curve uses another fluorescent lamp or infrared LED light as the light source. Since it is not critical compared to the case, the change in the amplitude level of the image when the lens is moved back and forth is small, and it is difficult to find the true peak value, so the following adjustment variations occur.

That is, there were one adjusted to the infrared LED light side and one adjusted to the fluorescent lamp side. The former gives a clear image when imaged under an infrared LED light source, while the image has a large blur when imaged under a fluorescent light source, and the opposite is the case. As described above, the variation during focus adjustment is large, and as a result, some images after focus adjustment may appear to be out of focus depending on the type of light source at the time of imaging. Even when the adjustment is performed under the fluorescent light source, there is a variation in the adjustment, though it is not so much as under the incandescent light source. This is because an incandescent lamp or a fluorescent lamp is not a light source having a spectral emission characteristic of a single wavelength like an infrared LED light source, but a light source having a spectral emission characteristic that spreads in a certain wavelength range.

Further, even if a fluorescent lamp is selected as a light source for illuminating the black-and-white stripe chart during focus adjustment, its spectral emission characteristics are different from one another and also change with time, which causes the focus position to shift. I was afraid.

In view of the above-mentioned problems, the present invention has a well-balanced focus in imaging under each light source of an incandescent lamp, a fluorescent lamp, and an infrared LED light, and as a result, a clear image can be displayed on a television set under any light source. It can be displayed on the main unit with a monitor, and when adjusting the focus with a light source whose spectral emission characteristics such as incandescent lamps and fluorescent lamps have a spread in a certain range of wavelength, while reducing the variation during focus adjustment. Provided is a focus adjustment method for a TV intercom apparatus capable of reducing a shift in focus position due to a difference in spectral emission characteristics of light sources, a change over time, and the like.

[0011]

A focus adjusting method for a television door phone apparatus according to the present invention achieves the above object, and the invention according to claim 1 provides a slave unit with a camera and a slave unit with the camera. In the focus adjustment method for a TV door phone, which consists of a base unit with a TV monitor connected by a transmission line, the spectral emission characteristics of the light source and the spectral sensitivity characteristics of the image sensor (CCD) are multiplied in order to reduce variations during focus adjustment. It is characterized in that focus adjustment is performed using a colored fringe chart so that the combined spectral characteristics have a sharp peak at a specific wavelength.

Therefore, when a black-and-white stripe chart is used, white reflects light of all wavelengths in the visible light region (black absorbs all light in the visible light region), so that the spectral emission of the light source is obtained. Light of all wavelengths appearing in the characteristics will contribute to the focus adjustment of the lens. If you use colored such as red and blue instead of white or white and black in this black and white striped chart, only light of a specific wavelength such as red and blue is reflected among all wavelengths in the visible light range, so If the spectral emission characteristics are limited to the visible light region, only light of a specific wavelength such as red or blue contributes to focus adjustment of the lens. In the latter case, the change in the amplitude of the image when the lens is moved back and forth becomes much more critical than in the former case, and the variation in focus adjustment can be reduced. In addition, it is possible to remove a considerable proportion of light source-dependent parts such as differences in spectral emission characteristics of light sources and changes with time.

Further, the invention according to claim 2 and claim 3 is a focus adjusting method for a TV intercom which comprises a slave unit with a camera and a master unit with a TV monitor connected to the slave unit with a camera by a transmission line. In the invention according to claim 1, red and black are used as colors of the specific colored striped chart,
By illuminating this red-black fringe chart with a light source having a spectral emission characteristic only in the visible light region and performing focus adjustment, it is possible to focus on a single wavelength of red wavelength (about 650 nm), which results in fluorescence. It is characterized in that it is possible to focus on an appropriate position between the position of the focus under the light source of light and the position of the focus under the light source of the infrared LED light.

As a result, a well-balanced focus is achieved in imaging under each light source of incandescent lamp, fluorescent lamp, and infrared LED light,
Under any light source, clear images can be displayed on the base unit with a TV monitor.

The invention according to claims 4 and 5 is an invention concerning means for detecting an amplitude level of a video (luminance) signal of a fringe portion of a fringe chart used for focus adjustment. In a fourth aspect of the present invention, in the focus adjusting method for a TV intercom apparatus according to the third aspect, the whole image is detected as a means for detecting the peak value of the level of the image (luminance) signal corresponding to the stripe portion of the stripe chart during the focus adjustment. In order to extract the part corresponding to the stripe part from the (luminance) signal,
6. A high-frequency component is extracted from the video (luminance) signal, and the peak value is evaluated by an averaged value in the entire area of the screen or a specific selected area. In the described invention, in the focus adjusting method for a TV intercom apparatus according to any one of claims 1 to 3, a peak value of a level of a portion corresponding to a stripe portion of a stripe chart of a video signal is adjusted during focus adjustment. As a means for detecting, the points at which the level of the luminance component of the video (luminance) signal is changing in the horizontal direction and the vertical direction of the imaging screen are extracted, and the change level at each point is the entire area of the screen or a specific selected area. It is characterized in that it is evaluated by the averaged value in.

Therefore, in particular, according to the invention of claim 5, the stripe chart of the invention of claim 1 or 2 does not need to be arranged vertically with respect to the image pickup screen of the camera, but can be arranged horizontally or obliquely. Becomes When the high-frequency correction is performed in the camera circuit, the horizontal adjustment may be easier than the vertical adjustment as the array of focus adjustment stripe charts. (If the stripe charts are arranged vertically, and if high-frequency correction is performed by the circuit, the amplitude level of the video (luminance) signal corresponding to the stripes will change even if the focus is slightly off the just focus position. Due to the high frequency correction on the circuit, the level at the position of the just focus does not change so much, and it may be difficult to adjust.) Further, according to the invention of claim 5, a subject other than the fringe chart can be used during focus adjustment. Like

Further, the invention according to claim 6 is a focus adjusting method for a TV intercom which comprises a slave unit with a camera and a master unit with a TV monitor connected to the slave unit with a camera by a transmission line. The colored stripe chart of the invention according to claim 1, as described above, as a subject used in this case,
Further, in place of the red-black stripe chart of the invention according to claim 2, a fine and uniform pattern, character or symbol composed of a specific color or red and black is used, and the invention according to claim 5 A feature that the focus of the camera is adjusted so that the average value of the change level at the change point of the brightness level in the horizontal direction and the vertical direction of the imaging screen becomes the largest and the subject is displayed as the clearest image. Is.

Therefore, as compared with the method of adjusting the amplitude level of the image (luminance) signal of the corresponding stripe portion using the stripe chart so as to take the peak value, the focus is actually adjusted by the human eye when the focus is adjusted. There is a merit that you can actually feel that.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a focus adjusting method for a TV door intercom apparatus according to the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic view showing a TV doorphone device for explaining an embodiment of a focus adjusting method for a TV doorphone device according to the present invention, and FIG. 2 is a slave unit with a camera of the TV doorphone device shown in FIG. 3 is a schematic view showing the structure of the substrate alone, FIG. 3 is a schematic view of a lens used in the camera-equipped slave unit of FIG. 1 as seen from above, and FIG. 4 is used in the camera-equipped slave unit of FIG. FIG. 5 is a schematic view of the lens seen from the side, FIG. 5 is a schematic view showing that the lens position of the camera is different between the fluorescent lamp light source and the infrared LED light source, and FIG. 6 is a dedicated jig for adjusting the focus of the child device with a camera. It is a schematic diagram.

Further, FIG. 7 is a schematic diagram of a video signal waveform of a corresponding stripe portion at the time of capturing a stripe chart during focus adjustment,
FIG. 8 is a schematic diagram showing a black-and-white chart during focus adjustment in the related art. White and black are vertically arranged at equal intervals, and a resolution of 150 TV lines or more can be confirmed. It is a schematic diagram showing a red-black chart during focus adjustment according to the present invention, in which red and black are vertically arranged at equal intervals and a resolution of 150 TV lines or more can be confirmed.

FIG. 10 is a diagram showing the spectral characteristics obtained by multiplying the spectral emission characteristics of the light source and the spectral sensitivity characteristics of the image pickup device (CCD), and FIG. 11 corresponds to the stripe portion of the stripe chart during focus adjustment. FIG. 12 is a block diagram showing a method for searching for a peak value from a video signal, and FIG. 12 is a block diagram showing a method for producing a signal representing the definition of an image of a subject during focus adjustment.

First, as shown in FIG. 1, the TV intercom apparatus includes a slave unit 1 with a camera and a master unit 3 with a TV monitor connected by a transmission line 2. In the figure, 4 is a television monitor. The internal structure of the child device 1 with a camera is shown in FIG.
As shown in FIG. 4, the lens barrel portion 8 of the lens is rotated counterclockwise with respect to the substrate 5, that is, by rotating the lens barrel portion 8 to slide the lens back and forth, focus adjustment becomes possible, and the lens master The lens 7 and the infrared LED 6 that can fix the master flange portion 9 of the lens and the lens barrel portion 8 with the lens fixing screw 10 provided on the flange portion 9 are provided.

As shown in FIG. 5, if the spectral emission characteristics of the light source incident on the lens 13 are different, the focal position of the lens 13 is different due to the difference in chromatic aberration of the lens 13. For example, the upper part of FIG. 5 shows the focus position when the light source is infrared LED light, and the lower part shows the focus position when the light source is a fluorescent lamp. Figure 5
Focusing on the position in the upper row gives a clear image under the fluorescent light source, but a blurred image under the infrared LED light source. In addition, focusing on the lower position in FIG.
The image becomes clear under the infrared LED light source, but becomes blurred under the fluorescent light source.

Therefore, the lens focus position of the camera is set at an appropriate position between the lens focus position 15 of the fluorescent light source 12 and the lens focus position 16 of the infrared LED light source 11 shown in FIG. By defining, under either light source of the fluorescent lamp light source 12 and the infrared LED light source 11, a well-balanced focus is achieved, and a clear image is displayed on the monitor 4 of the base unit 3 of the TV doorphone device under both light sources. Is possible.

The red and black fringe chart is illuminated by a light source having a spectral emission characteristic only in the visible light region, an image thereof is captured, and the red wavelength, which is a single wavelength, is focused to thereby obtain the fluorescent lamp and the infrared LED. The lens focus position of the camera is set at an appropriate position between the lens focus positions of both light sources. In addition, the wavelength of the light incident on the lens is a single red wavelength of the fringe chart, and the lens focus position is less displaced due to the difference in the illumination light source and the change over time.

FIG. 6 shows an example of a focus adjustment jig according to the present invention. A focus adjustment jig 17 provided in a dark box is provided with a camera-equipped slave unit 1, an illuminating light source 25, and the like as shown in FIG. As a subject, there is provided a striped chart 24 in which red and black are arranged in a vertical row and arranged at a predetermined distance from the handset 1 with a camera. As the light source for illumination, a light source having a spectral emission characteristic only in the visible light region is used, but in the case of a light source containing infrared light or ultraviolet light in addition to visible light, an optical filter 19 for cutting them is provided. For example, when a fluorescent lamp is used, since it does not contain infrared light but contains ultraviolet light, an ultraviolet light cut filter is provided. However, a red-black stripe chart is used as the stripe chart. In this case, neither red nor black reflects ultraviolet light, so that the optical filter 19 is not necessary when the illumination light source is a fluorescent lamp.

When the fringe chart 24 is imaged by using the jig 17 for focus adjustment of the present invention, a video signal waveform 20 as shown in FIG.
Is output. While observing the waveform 20, the lens 7 is moved back and forth to adjust the focus so that the amplitude level 22 of the video (luminance) signal 21 corresponding to the stripe portion of the red-black stripe chart 24 has a peak value. At this time, when the lens 7 is moved back and forth, the image (luminance) signal 2 corresponding to the chart stripe portion
The change in the amplitude level 22 of 1 is very large, that is, the change is critical, and therefore the variation during adjustment is small.

The stripe chart 24 is a red-black stripe chart in which red and black are vertically arranged at equal intervals and a resolution of 150 TV lines or more can be confirmed. The reason for using this is that the image corresponding to the stripe portion of the chart ( The amplitude waveform of the (luminance) signal is almost the same on each line of the screen and has periodicity.
This is because it is easy to check the level with a measuring instrument such as an oscilloscope, and it is easy to find the peak value of the level.

By using a method of extracting a signal representing the definition of an image when a subject is picked up from the video signal as a whole and observing the peak value by observing the magnitude of this signal, it is possible to determine a non-subject as a subject. In addition to being able to use evenly-spaced striped charts, horizontally arranged striped charts, etc., not only charts but also finely and evenly distributed repetitive or non-repeating patterns, letters, or symbols can be used. Like

Further, red and black are used as the two colors of the stripe chart because black absorbs light of all wavelengths in the visible light region, and therefore only light of red wavelength is used in focus adjustment. Is present and it is easy to focus on this wavelength. Other colors such as blue and yellow can be used in addition to black, but in this case, there are two wavelengths of light, and the amplitude level 22 of the video (luminance) signal 21 corresponding to the stripe portion of the stripe chart is 2 It is necessary to be careful because there are two peaks, but if you adjust it so that it is not mistaken, the fluctuation of the focus position during focus adjustment and the independence of the illumination light source are the same as in the red and black stripe chart. .

Further, as a method for detecting the peak value of the video (luminance) signal corresponding to the stripe portion of the above-mentioned stripe chart, the video (luminance) signal corresponding to the stripe portion is used as it is without being processed and its peak value is used. There is a method of searching for and a method of processing and searching for the peak value. An example of the latter method is shown in FIG. By inputting the video (luminance) signal a as the entire fringe chart to the high-pass filter 31, only the fringe portion of the fringe chart, which is a high frequency component, is extracted and averaged by the detection unit 32 and the smoothing unit 33. get b. The average value b is the average value of the amplitude level 22 of the video (luminance) signal 21 corresponding to the stripe portion of the stripe chart, and the peak value is searched for by observing the magnitude.

The method of producing the above-mentioned signal representing the definition of the image is as follows. The video (luminance) signal c of the entire subject is A / D converted by the A / D converter 34, and then temporarily stored in the memory A35, and the memory A35 has a luminance level equal to or higher than the luminance level in the horizontal and vertical directions of the screen. The changing point is sequentially scanned and searched, and the changing level d is stored in another memory B36.
I will remember it above. When the average value e is obtained from the change level at each change point stored in the memory B36, this average value e becomes a signal representing the definition of the screen, and the focus may be focused so that it becomes the largest. When obtaining the average value, weighting may be performed to increase the weight near the center of the screen and decrease the weight around the periphery so that the focus is focused on the center of the screen.

[0034]

The present invention as described above, according to the present invention includes, in the focus adjustment method of TV door device, upon adjustment of the focus of the camera, as a subject to be used, the Except white red instead of the traditional black and white stripes Chart by using two kinds of specific definition object colors with a containing two specific red except stripes chart or white colored, it is possible to focus on a specific wavelength, focusing In this way, it is possible to reduce the variation in the focal position during operation, and to reduce the deviation of the focal position due to the difference in the spectral emission characteristics of the light source that illuminates the subject and the change over time, and to reduce the dependency of the light source when adjusting the focal position. can do. Further, this is characterized in that the focus can be adjusted to an appropriate position between the focus position under the fluorescent light source and the focus position under the infrared LED light source. As a result, it is possible to achieve a well-balanced focus during image pickup under each light source of incandescent lamp, fluorescent lamp, and infrared LED light, and a clear image can be displayed on the master unit with a TV monitor under any light source. .

Further, if red is selected as the specific wavelength and focus adjustment is performed using a red-black stripe chart or a red-black fine object, the visible light region to the infrared LED light region as in a camera of a TV door phone. For cameras that require a wide range of light wavelengths up to, a clear image can be displayed on a TV monitor without any bias under a light source of any wavelength. Further, this focus adjustment method can be applied to not only the camera of the TV door phone but also other cameras.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a TV door phone device for explaining an embodiment of a focus adjusting method for a TV door phone device according to the present invention.

FIG. 2 is a schematic diagram showing a configuration of a substrate alone of a slave unit with a camera of the TV doorphone apparatus of FIG.

3 is a schematic plan view of a lens used in a child device with a camera of the TV doorphone apparatus of FIG.

FIG. 4 is a schematic side view of a lens used in a child device with a camera of the TV doorphone apparatus of FIG.

FIG. 5 is a schematic view showing a lens focus position by a fluorescent lamp light source and an infrared LED light source for explaining an embodiment of a focus adjusting method for a TV door intercom device of the present invention.

FIG. 6 is a schematic view showing a jig for focus adjustment of the TV door phone apparatus of FIG.

7 is a schematic diagram showing a waveform of a video signal output from a child device with a camera of the TV door intercom apparatus of FIG.

FIG. 8 is a schematic view showing a stripe chart in which white and black are vertically arranged as a subject as an object for explaining an embodiment of a focus adjusting method for a television door intercom apparatus according to the present invention.

FIG. 9 is a schematic diagram showing a stripe chart in which red and black are vertically arranged as a subject as an object for explaining an embodiment of a focus adjusting method for a TV door intercom apparatus according to the present invention.

FIG. 10 is a diagram showing a spectral characteristic obtained by multiplying a spectral emission characteristic of a light source and a spectral sensitivity characteristic of an image sensor for explaining an embodiment of a focus adjusting method for a TV door intercom device of the present invention.

FIG. 11 is a block diagram showing a method of finding a peak value from a video signal corresponding to a stripe portion of a stripe chart for explaining an embodiment of a focus adjusting method for a TV door phone apparatus according to the present invention.

FIG. 12 is a block diagram showing a method of producing a signal representing the definition of an image of a subject for explaining the embodiment of the focus adjusting method for the television door intercom device of the present invention.

[Explanation of symbols]

1 Handset with camera 2 transmission lines Base unit with 3 TV monitors 4 TV monitor 5 substrates

Claims (6)

(57) [Claims] 1. A focus adjustment method for a TV doorphone device comprising a master unit with a TV monitor connected to a slave unit with a camera via a transmission line, wherein a focus distance is set at a predetermined distance from the camera.
White Place two specific fringe chart with a different color fringes colors from each other adjacent arranged stripes using colors including dividing-out red, whereby a light source having a spectral emission characteristic of only the visible light region The fluorescent lamp is illuminated by adjusting the focus of the camera so that the level of the video signal corresponding to the stripe portion of the colored stripe chart has a peak value and the colored stripe chart is displayed as the clearest image. A focus adjusting method for a TV intercom apparatus, comprising: focusing the camera at an appropriate position between a focus position under a light source and a focus position under a semiconductor infrared light emitting device light source. 2. A focus adjustment method for a TV door phone apparatus comprising a master unit with a TV monitor connected to a slave unit with a camera via a transmission line, wherein a red and black stripe is used at a predetermined distance from the camera. Arrange adjacent red and black stripe charts in which adjacent stripes have different colors, illuminate this with a light source having a spectral emission characteristic only in the visible light region, and the level of the video signal corresponding to the stripe portion of the red and black stripe chart is By taking the peak value and adjusting the focus of the camera so that the red and black stripe chart is displayed as the clearest image, the focus position under the fluorescent light source and the focus position under the semiconductor infrared light emitting device light source A method for adjusting the focus of a TV intercom device, which comprises focusing the camera at an appropriate position between the two. 3. The focus adjustment method for a TV door phone apparatus according to claim 1 or 2, wherein the stripe chart used is one in which stripes are vertically arranged at equal intervals and a resolution of 150 TV lines or more can be confirmed. A method for adjusting the focus of a featured TV intercom device. 4. The focus adjustment method for a TV door phone apparatus according to claim 3, wherein the means for detecting the peak value of the level of the video signal corresponding to the stripe portion of the stripe chart during focus adjustment is a stripe portion from the entire video signal. In order to extract a portion corresponding to, a high frequency component is extracted from the video signal,
A focus adjusting method for a TV intercom apparatus, characterized in that the peak value is evaluated by an averaged value in the entire area of the screen or a specific selected area. 5. The focus adjusting method for a TV intercom apparatus according to claim 1, wherein a peak value of a level of a portion corresponding to a stripe portion of a stripe chart of a video signal is adjusted during focus adjustment. As a means for detecting, the points at which the level of the luminance component of the video signal changes in the horizontal and vertical directions of the image pickup screen are extracted, and the change level at each point is averaged over the entire area of the screen or a specific selected area. A method of adjusting the focus of a TV intercom device, which is characterized in that the evaluation is performed by 6. A 2 include the focus adjustment method of the TV door apparatus according to claim 1 or claim 2, wherein the Except white red instead of stripes chart or the red and black stripes chart with the colors during focusing A fine and evenly distributed repeat made up of a specific color of type or red and black,
Alternatively, a subject consisting of a non-repeating pattern or a list of characters and symbols is imaged, and the average value of the change levels at the change points of the brightness level in the horizontal direction and the vertical direction of the imaging screen for the subject becomes the largest, and A focus adjusting method for a TV intercom device, which comprises adjusting the focus of the camera so as to be displayed as a clear image.