Electronic-endoscope light quantity controlling apparatus

• US 6,254,531 B1
• Filed: 03/08/1999
• Issued: 07/03/2001
• Est. Priority Date: 03/10/1998
• Status: Expired due to Fees

• Current Assignee: Fujinon Corporation (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Photo Optical Co. Ltd (Fujifilm Holdings Corporation)
• Inventors: Yamanaka, Kazuhiro, Higuchi, Mitsuru, Takeuchi, Shinji
• Primary Examiner(s): MULCAHY, JOHN M
• Application Number:
  US09/264,240
• Time in Patent Office: 848 Days
• Field of Search: 600/178-181, 600/109, 600/160, 348/68, 348/69, 362/574
• US Class Current: 600/178
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: A61B 1/0655 Control therefor
• CPC Class Codes: A61B 1/0669 at proximal end of an endoscope
• CPC Class Codes: H04N 23/555 for picking-up images in sites, inaccessible due to their dimensions or hazardous conditions, e.g. endoscopes or borescopes
• CPC Class Codes: H04N 23/74 by influencing the scene brightness using illuminating means

Abstract

The present invention is an electronic endoscope apparatus that can appropriately compensate for the lack of light quantity caused by a delayed response from a shielding mechanism in using the all-pixel reading system to form a high-quality image. In this apparatus, for a moving image, a pixel mix signal is read out from a CCD to reproduce motions faithfully. For a still image, to improve the image quality, a shielding period set by the shielding plate is used to read out all the pixels obtained by the CCD during a single exposure in order to form a pixel mix signal using a mixing circuit. A lamp characteristic memory stores table data indicating the characteristic between the lamp voltage of the current lamp and the quantity of outgoing light so that based on this data, a lamp voltage higher than in moving images is supplied to the lamp during the exposure for still-image formation. This configuration compensates for the lack of light quantity caused by a delayed response from the shielding plate to provide an appropriately bright still image. The lack of light quantity can also be compensated for by storing in the memory the characteristic between a diaphragm value and the outgoing light quantity and increasing the numerical aperture of the diaphragm based on the characteristic data.

Claims

1. An electronic endoscope apparatus controlling the quantity of light, comprising:

a light source for irradiating an observed object with light;

outgoing light quantity varying means for variably adjusting the quantity of outgoing light from the light source based on a predetermined control value;

shielding means for intercepting light from said light source to set a shielding period for an all-pixel reading system;

a signal processing circuit for executing the all-pixel reading system that uses said shielding period to read out signals for all the signals accumulated in an image pickup device during a single exposure;

storage means for storing characteristic data between said control value and said quantity of outgoing light; and

light quantity controlling means for controlling said outgoing light quantity adjusting means based on the characteristic data stored in the storage means to adjust the quantity of outgoing light from said light source, thereby compensating for the lack of light quantity caused by a delayed response from said shielding means for a shielding operation.

2. An electronic endoscope apparatus controlling the quantity of light according to claim 1, wherein:

said outgoing light quantity varying means comprises a lamp driving means for varying a lighting voltage for a light source lamp,

said storage means storing the characteristic data between the lighting voltage for said light source lamp and said quantity of outgoing light,

said light quantity controlling means varying the lighting voltage for said light source lamp based on the characteristic data stored in said storage means to adjust the quantity of outgoing light from said light source, thereby compensating for the lack of light quantity caused by a delayed response from said shielding means for a shielding operation.

3. An electronic endoscope apparatus controlling the quantity of light according to claim 2, wherein a light quantity sensor for detecting the quantity of outgoing light from said light source is provided to store in said storage means the characteristic data between said lamp lighting voltage and said outgoing light quantity based on an output from the light quantity sensor.

4. An electronic endoscope apparatus controlling the quantity of light according to claim 3, wherein said light quantity controlling means executes a lamp characteristic detection mode that uses said optical sensor to automatically create and store the characteristic data on said lamp lighting voltage.

5. An electronic endoscope apparatus controlling the quantity of light according to claim 1, wherein said outgoing light quantity varying means comprises a diaphragm for adjusting the quantity of outgoing light from a light source lamp,

said storage means storing the characteristic data between the diaphragm value of said diaphragm and said quantity of outgoing light,

said light quantity controlling means varying the numerical aperture of said diaphragm based on the characteristic data stored in said storage means to adjust the quantity of outgoing light from said light source, thereby compensating for the lack of light quantity caused by a delayed response from said shielding means for a shielding operation.

6. An electronic endoscope apparatus controlling the quantity of light according to claim 5, wherein a light quantity sensor for detecting the quantity of outgoing light from said light source is provided to store in said storage means the characteristic data between said diaphragm value and said outgoing light quantity based on an output from the light quantity sensor.

7. An electronic endoscope apparatus controlling the quantity of light according to claim 6, wherein said light quantity controlling means executes a diaphragm-value characteristic detection mode that uses said optical sensor to automatically create and store the characteristic data on said diaphragm value.

8. An electronic endoscope apparatus controlling the quantity of light, comprising:

a light source for irradiating an observed object with light;

outgoing light quantity varying means for variably adjusting the quantity of outgoing light from the light source based on a predetermined control value;

shielding means for intercepting light from said light source to set a shielding period for an all-pixel reading system;

a signal processing circuit for executing a pixel mix reading system at the output of the image pickup device for mixing together pixels accumulated in said image pickup device in such a way that vertically arranged lines are mixed together and then outputting the resulting pixels to form a moving image and an all-pixel reading system for forming a still image by using said shielding period to read out all pixels accumulated in the image pickup device during a single exposure;

storage means for storing characteristic data between said control value and said quantity of outgoing light; and

light quantity controlling means for controlling said outgoing light quantity adjusting means based on the characteristic data stored in the storage means to adjust the quantity of outgoing light from said light source, thereby compensating for the lack of light quantity caused by a delayed response from said shielding means for a shielding operation.