Apparatus and method for histogram analysis of image and luminance compensation apparatus using the same

An apparatus for luminance compensation through a histogram analysis of an image, the apparatus comprising:

• a histogram analysis unit for calculating a first histogram by using all pixels of said input image, performing a blocking operation for dividing the input image into predetermined pixel blocks, calculating a second histogram by using a representative pixel of each block obtained by the blocking operation, performing a test operation to determine if characteristics of the first and second histograms satisfy a predetermined identity criterion, and calculating and outputting a third histogram of the input image by using the representative pixels obtained by the blocking operation when it has been determined that the predetermined identity criterion is satisfied;
• a luminance compensation function generation unit for calculating cumulative distribution of the histogram, and generating a mapping function for luminance compensation based on the cumulative distribution;
• and
• a mapping unit for compensating a luminance value of the input image according to the mapping function generated by the luminance compensation function generation unit.

An apparatus for luminance compensation through a histogram analysis of an image, the apparatus comprising:

• a histogram analysis unit for performing a blocking operation for dividing an input image into predetermined pixel blocks, and calculating and outputting a histogram of the input image by using a representative pixel of each block obtained by the blocking;
• a luminance compensation function generation unit for calculating cumulative distribution of the histogram, and generating a mapping function for luminance compensation based on the cumulative distribution;
• and
• a mapping unit for compensating a luminance value of the input image according to the mapping function generated by the luminance compensation function generation unit.

A method for luminance compensation through a histogram analysis of an image, the method comprising the steps of:

• calculating a first histogram by examining all pixels of each of a plurality of predetermined input image frames, and determining a type of the first histogram as a reference histogram type;
• calculating a second histogram by examining a representative pixel of each block obtained by a blocking operation, the blocking operation dividing each of the input image frames into pixel blocks according to a plurality of predetermined sizes, and determining a type of the second histogram as a comparison histogram type;
• checking an identity between the reference histogram types and the comparison histogram types, and obtaining a block which has a largest size while satisfying an identity rate with respect to a predetermined reference value;
• and
• calculating a third histogram by performing a blocking operation for the input image frame based on the obtained largest block and actually outputting the third histogram.

An apparatus for luminance compensation through a histogram analysis of an image, the apparatus comprising:

• a processor in communication with a memory, the processor executing the steps of:
• determining a first histogram of all pixels of each of a plurality of input predetermined image frames, and determining a type of the first histogram as a reference histogram type;
• determining a second histogram by examining a representative pixel of each block obtained by a blocking operation;
• determining a type of the second histogram as a comparison histogram type;
• checking an identity between the reference histogram types and the comparison histogram types, and obtaining a block which has a largest size while satisfying an identity rate with respect to a predetermined reference value;
• and
• calculating a third histogram by performing a blocking operation for the input image frame based on the obtained largest block and outputting the third histogram.