Endoscopic image enhancement using contrast limited adaptive histogram equalization (clahe) implemented in a processor

An endoscope system comprising:

• an endoscope including a first viewing element;
• and
• a control unit operatively coupled to the endoscope by a cable, wherein the control unit comprises:
• a base board module;
• one or more processing boards that implement a contrast limited adaptive histogram equalization (CLAHE) algorithm to enhance images obtained by the first viewing element, wherein the one or more processing boards perform the steps of:
• receiving a first video stream from the first viewing element,
• building first histogram information based on a first portion of the first video stream,
• building second histogram information based on a second portion of the first video stream,
• converting the first histogram information into first cumulative distribution function values including applying a first clipping threshold to the first histogram information,
• converting the second histogram information into second cumulative distribution function values including applying a second clipping threshold to the second histogram information, wherein the second clipping threshold is different from the first clipping threshold,
• obtaining a first plurality of frames from the first video stream,
• rearranging the first plurality of frames to generate a plurality of first delayed video streams,
• generating a first enhanced video stream based on the plurality of first delayed video streams, the first cumulative distribution function values, and the second cumulative distribution function values, and
• sending an output video stream indicative of the first enhanced video stream to a display.

A method of enhancing images obtained by an endoscope system using a contrast limited adaptive histogram equalization (CLAHE) process, wherein said endoscope system comprises (a) one or more processing boards configured to implement said process, and (b) an endoscope operatively coupled to the one or more processing boards, the endoscope including a first viewing element, said method comprising the steps of:

• receiving a first video stream from the first viewing element;
• splitting the first video stream into a plurality of tiles, wherein units of the tile heights are in video lines and units of the tile widths are in pixels;
• building histogram information based on the plurality of tiles;
• converting the histogram information into cumulative distribution function values;
• obtaining the first video stream as a first plurality of frames;
• rearranging the first plurality of frames to generate a first delayed video stream;
• generating an enhanced video stream, using the first delayed video stream and the cumulative distribution function values;
• and
• displaying an output video stream indicative of the enhanced video stream.

A non-transient computer readable medium containing program instructions for causing a computer to perform a method of enhancing images obtained by a first viewing element in an endoscope system using a contrast limited adaptive histogram equalization (CLAHE) process, wherein said endoscope system comprises a processor configured to implement said process, and an endoscope operatively coupled to the processor, the endoscope including the first viewing element, said method comprising the steps of:

• receiving a first video stream from the first viewing element,
• building first histogram information based on a first component of the first video stream,
• building second histogram information based on a second component of the first video stream,
• converting the first histogram information into first cumulative distribution function values including applying a first clipping threshold to the first histogram information,
• converting the second histogram information into second cumulative distribution function values including applying a second clipping threshold to the second histogram information, wherein the second clipping threshold is different from the first clipping threshold,
• obtaining a first plurality of frames from the first video stream,
• rearranging the first plurality of frames to generate a plurality of first delayed video streams,
• generating a first enhanced video stream based on the plurality of first delayed video streams, the first cumulative distribution function values, and the second cumulative distribution function values, and
• sending an output video stream indicative of the first enhanced video stream to a display.