Digital image filters and related methods for image contrast enhancement

Patent metadata

Field	Value
Publication number	US-10055827-B2
Application number	US-56058109-A
Country	US
Kind code	B2
Filing date	Sep 16, 2009
Priority date	Sep 16, 2008
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

Digital image filters and related methods for image contrast enhancement are disclosed. According to one aspect of the method, an invariant brightness level is initially determined. For each pixel of an input image, the invariant brightness level is subtracted from the input brightness of the pixel. The resulting value is multiplied with a contrast adjustment constant. After that, the invariant brightness level is added. Further aspects of the method can involve histogram equalization.

First claim

The invention claimed is:

1. A visual prosthesis comprising:
a video input device for providing video data;
a video processing unit, including a digital signal processor, receiving the video data from the video input device and converting the video data into a video output image, including an array of pixels, the video processing unit including:
an image contrast enhancement filter based on an invariant brightness level, and the formula Iout=(Iin−L) C+L, where Iout is output intensity, Iin is input intensity, L is the invariant brightness level, and C is a predetermined multiplier, and each pixel's difference from the invariant brightness level, where L is determined by segmentating the image to find objects, calculating an average brightness for each object, and setting L to be the darkest average brightness;
a video filter processor producing the video output image;

a telemetry engine transmitting the video output image; and

a neural stimulation system suitable to receive the video output image and to stimulate visual percepts according to the video output image.

2. The visual prosthesis of claim 1 , wherein the image contrast enhancement filter is based on image histogram equalization, so that an output image output by the image contrast enhancement filter has an output image histogram which is an equalized version of the input image histogram.

3. The visual prosthesis of claim 2 , wherein image histogram equalization operates through a nonlinear monotonic scaling function.

4. The visual prosthesis of claim 2 , wherein the image contrast enhancement filter operates in the time domain.

5. The visual prosthesis of claim 1 , wherein filtering through the contrast enhancement filter is automatically set.

6. The visual prosthesis of claim 2 , wherein filtering through the contrast enhancement filter is applied automatically on every video frame of the video data.

7. The visual prosthesis of claim 2 , wherein filtering through the contrast enhancement filter is an adaptive filtering.

8. The visual prosthesis of claim 7 , wherein the adaptive filtering depends on a luminance distribution of input images at any instant of time.

9. The visual prosthesis of claim 2 , wherein the image histogram equalization is based on a temporal average.

Assignees

• Zhou Chunhong
• Roy Arup
• Mcclure Kelly H
• Second Sight Medical Products Inc

Inventors

• Zhou Chunhong
• Roy Arup
• Mcclure Kelly H

Classifications

• G06T2207/10016

  Video; Image sequence · CPC title

• G06T5/40 Primary

  using histogram techniques · CPC title

• G06T5/009

  Physics · mapped topic

• A61N1/36046

  of the eye · CPC title

• G06T5/92

  based on global image properties · CPC title