Television – Camera – system and detail – Combined image signal generator and general image signal...
Reexamination Certificate
1996-11-21
2001-11-20
Garber, Wendy R. (Department: 2612)
Television
Camera, system and detail
Combined image signal generator and general image signal...
C348S364000
Reexamination Certificate
active
06320615
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a light level detecting method, and more particularly, to a light level detecting method for detecting the level of the environment light when photographing and recording an image, and providing the light level information to the user.
A conventional light level detecting method for an image photographing and recording apparatus is performed by a separate light detecting sensor as shown in
FIG. 1. A
light detecting sensor
11
detects the level of the environment light, and transmits that information to a control unit
12
. The control unit
12
then determines whether the environment light is less than a predetermined reference level. If so, the control unit
12
outputs a light level control signal to an indicator
13
, which indicates the states of either an insufficient light or a total lack of light. However, the inclusion of the separate light detecting sensor inevitably leads to an increase in the production costs.
Moreover, using a separate sensor makes it difficult to precisely determine whether the amount of light is sufficient. That is, depending on the characteristics of the lens, the iris, or the charge coupled device (CCD), the amount of light actually reaching the image photographing and recording apparatus may be different from the available environment light.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a light detecting method using the automatic gain control of an electrically transformed image signal. According to the present invention the actual signal of the image recording process is used. Consequently, the need for a separate light sensor is obviated.
To achieve the above object, there is provided a light detecting method employed in an image photographing and recording device, the light detecting method includes the steps of:
(a) setting up a reference value corresponding to the highest amount of light which requires an automatic gain control;
(b) measuring the amount of light of the input optical signal;
(c) calculating a comparative value corresponding to the measured amount of light, wherein the comparative value controls the performance of the automatic gain control;
(d) comparing the reference value with the comparative value; and
(e) determining that the amount of light is insufficient when the result of the comparing step falls within a predetermined gain control range.
REFERENCES:
patent: 4972265 (1990-11-01), Tanaka et al.
patent: 5579049 (1996-11-01), Shimaya et al.
patent: 5604537 (1997-02-01), Yamazaki et al.
patent: 5625411 (1997-04-01), Inuiya et al.
patent: 5737018 (1998-04-01), Shimizu
patent: 5818975 (1998-10-01), Goodwin et al.
patent: 5883666 (1999-03-01), Kyuma et al.
Garber Wendy R.
Samsung Electronics Co,. Ltd.
Sughrue Mion Zinn Macpeak & Seas, PLLC
Vu Ngoc-Yen
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