System and Method for Processing Video Images Generated By A Multiple Viewing Elements Endoscope

• US 20160174827A1
• Filed: 12/14/2015
• Published: 06/23/2016
• Est. Priority Date: 12/18/2014
• Status: Active Grant

• Current Assignee: EndoChoice Incorporated (Boston Scientific Corporation)
• Original Assignee: EndoChoice Incorporated (Boston Scientific Corporation)
• Inventors: Kronman, Achia, Sidar, Itay, Davidson, Tal
• Granted Patent: US 10,123,684 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: A61B 1/00009 of image signals during a use of endoscope
• CPC Class Codes: A61B 1/00177 for 90 degrees side-viewing
• CPC Class Codes: A61B 1/00181 for multiple fixed viewing angles A61B1/00193 takes precedence
• CPC Class Codes: A61B 1/042 characterised by a proximal camera, e.g. a CCD camera
• CPC Class Codes: A61B 1/045 Control thereof
• CPC Class Codes: A61B 1/05 characterised by the image sensor, e.g. camera, being in the distal end portion
• 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 23/71 Circuitry for evaluating the brightness variation
• CPC Class Codes: H04N 23/76 by influencing the image signals
• CPC Class Codes: H04N 25/58 involving two or more exposures
• CPC Class Codes: H04N 25/611 Correction of chromatic aberration
• CPC Class Codes: H04N 25/621 for the control of blooming
• CPC Class Codes: H04N 25/71 Charge-coupled device [CCD] sensors; Charge-transfer registers specially adapted for CCD sensors
• CPC Class Codes: H04N 25/76 Addressed sensors, e.g. MOS or CMOS sensors
• CPC Class Codes: H04N 3/1568 for disturbance correction or prevention within the image-sensor, e.g. biasing, blooming, smearing correction circuits H04N25/62

Abstract

An endoscope video processing system applies a blooming control feature to image frames of video data signals generated by viewing elements in the endoscope tip. A reduced digital gain is applied to a luminance (Y) component of the video data signal to generate an attenuated signal. An average luminance value of pixels neighboring a pixel of the attenuated signal is calculated and a function of the average luminance value is determined to generate a smoothly transitioning digital gain. The smoothly transitioning digital gain is conditioned using weights to generate a customizable digital gain, and the customizable digital gain is applied to the attenuated signal. This Local Blooming Control (LBC) facilitates a higher luminance digital gain in darker portions while maintaining a low or no luminance digital gain in brighter portions, within the same image frame.

Claims

1. An endoscope video processing system for controlling blooming in an image frame of a video data signal generated by a viewing element of an endoscope, to facilitate an increased luminance digital gain in regions of a first brightness within the image frame while maintaining a decreased luminance digital gain in regions of a second brightness, wherein the first brightness is lower than the second brightness, said video processing system comprising:

a processor;

a memory;

a digital signal processor for applying a reduced digital gain to a luminance (Y) component of the video data signal to generate an attenuated signal, wherein the reduced digital gain is defined by a weight; and

a local blooming control module for;

calculating an average luminance value of luminance levels of a plurality of pixels neighboring a pixel of the attenuated signal;

operating a function on the average luminance value to generate a smoothly transitioning digital gain;

conditioning the smoothly transitioning digital gain using said weight to generate a customizable digital gain; and

applying the customizable digital gain to the attenuated signal.

2. The endoscope video processing system of claim 1, wherein said weight comprises a first weight and a second weight.

3. The endoscope video processing system of claim 2, wherein the reduced digital gain meets a condition where a sum of the first weight and the second weight is in the range of 1.0 to 5.0.

4. The endoscope video processing system of claim 2, wherein the first weight is a constant value while the second weight has a value depending on surrounding luminance.

5. The endoscope video processing system of claim 1, wherein the average luminance value is calculated using Gaussian weights.

6. The endoscope video processing system of claim 1, wherein the function is a sigmoid function.

7. The endoscope video processing system of claim 6, wherein a center point of the sigmoid function approximates 240/(1+second weight), wherein said viewing element of the endoscope comprises a CCD sensor.

8. The endoscope video processing system of claim 6, wherein a center point of the sigmoid function approximates 255/(1+second weight), wherein said viewing element of the endoscope comprises a CMOS sensor.

9. The endoscope video processing system of claim 6, wherein a center point of the sigmoid function approximates 100/(1+second weight), wherein said viewing element of the endoscope comprises a CMOS sensor.

10. The endoscope video processing system of claim 6, wherein a center point of the sigmoid function decreases as the second weight increases and said center point increases as the second weight decreases.

11. The endoscope video processing system of claim 1, wherein the customizable digital gain meets a plurality of conditions, said plurality of conditions including at least one of:

a value of said digital gain approaches 1.0 as a brightness of a region of the image frame nears maximal value;

said digital gain has an upper limit of 5.0 in a region of the image frame that, relative to all other regions in said image frame, is darkest;

or

said digital gain transitions from a region of a first brightness to a region of a second brightness, wherein the first brightness is greater than the second brightness, in a smooth manner.

12. A method of controlling blooming in a plurality of regions of an image frame of a video data signal generated by a viewing element of an endoscope, said method being implemented by the controller of the endoscope, the method comprising:

attenuating a luminance (Y) component of the video data signal to generate an attenuated signal, wherein the attenuation factor meets a condition such that a summation of a first weight K₁ and a second weight K₂ approximates a value equal to or less than 5.0;

applying a Gaussian function to luminance levels of a plurality of pixels neighboring a given pixel of the attenuated signal to generate an average luminance signal Gaussian(Y);

applying a sigmoid function to the average luminance signal to generate a modified signal sigmoid(Gaussian(Y)); and

applying a digital gain to the attenuated signal, wherein the digital gain is determined by applying weights to the modified signal sigmoid (Gaussian(Y)).

13. The method of claim 12, wherein the weights comprises a first weight K₁ and a second weight K₂, wherein K₁ is a constant value and K₂ has a value depending on surrounding luminance.

14. The method of claim 12, wherein a center point of the sigmoid function approximates 240/(1+K₂), wherein said viewing element of the endoscope comprises a CCD sensor.

15. The method of claim 12, wherein a center point of the sigmoid function approximates 255/(1+second weight), wherein said viewing element of the endoscope comprises a CMOS sensor.

16. The method of claim 12, wherein a center point of the sigmoid function approximates 100/(1+second weight), wherein said viewing element of the endoscope comprises a CMOS sensor.

17. The method of claim 12, wherein a center point of the sigmoid function decreases as the second weight K₂ increases and said center point increases as the second weight K₂ decreases.

18. The method of claim 12, wherein the value of said digital gain approaches 1.0 as brightness of a region of the image frame nears maximum value.

19. The method of claim 12, wherein the value of said digital gain has an upper limit of 5.0 in a region of the image frame that, relative to all other regions in an image frame, is the darkest.

20. The method of claim 12, wherein said digital gain transitions from a region of a first brightness to a region of a second brightness, wherein the first brightness is greater than the second brightness, in a smooth manner.

21. An endoscope video processing system for controlling blooming in an image frame of a video data signal generated by a viewing element of an endoscope, to facilitate an increased luminance digital gain in regions of a first brightness within the image frame while maintaining a decreased luminance digital gain in regions of a second brightness, wherein the first brightness is lower than the second brightness, said video processing system comprising a processor and memory for executing the steps of:

applying a reduced digital gain to a luminance (Y) component of the video data signal to generate an attenuated signal, wherein the reduced digital gain is defined by a weight;

calculating an average luminance value of luminance levels of a plurality of pixels neighboring a pixel of the attenuated signal;

operating a function on the average luminance value to generate a smoothly transitioning digital gain;

conditioning the smoothly transitioning digital gain using said weight to generate a customizable digital gain; and

applying the customizable digital gain to the attenuated signal.