Statistic calculating method using a template and corresponding sub-image to determine similarity based on sum of squares thresholding

• US 6,898,318 B2
• Filed: 03/12/2001
• Issued: 05/24/2005
• Est. Priority Date: 12/25/1996
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Hotta, Takashi
• Primary Examiner(s): COUSO, YON JUNG
• Application Number:
  US09/802,958
• Publication Number:
  US 20010031086A1
• Time in Patent Office: 1,534 Days
• Field of Search: 382/151, 382/205, 382/209, 382/216, 382/218, 382/270
• US Class Current: 382/209
• CPC Class Codes: G06T 7/20 Analysis of motion motion estimation for coding, decoding, compressing or decompressing digital video signals H04N19/43, H04N19/51
• CPC Class Codes: G06V 10/7515 Shifting the patterns to accommodate for positional errors

Abstract

An image processing apparatus obtains a sum A of image data values of pixels in a template image, a sum B of squares of image data values of pixels in a template image, a sum C of image data values of pixels in a sub-image to be processed, of a search image, a sum D of squares of image data values of pixels in the sub-image of the template image, further obtains a threshold value F in advance by using the obtained values A, B, C and D, the number P of pixels in the template image, and the preset value E. Moreover, the apparatus obtains a square of each difference between an image data value of each pixel in the sub-image and that of a corresponding pixel in the template image, and performs cumulative addition for each obtained squares. If the result of cumulative addition exceeds the above-mentioned threshold value, the apparatus closes processing evaluation of a similarity between the sub-image and the template image. Furthermore, the apparatus recursively obtains a moving-average value of image data values of pixels in a rectangular region to be presently processed, by using a moving-average value for a rectangular region which was previously processed and image data read from a first memory and a second memory, each memory stores image data by one line pixels of the image, which include image data of pertinent pixels in the rectangular regions.

Claims

1. An image processing method of reading image data of pixels in an image to be processed from, from a memory for storing an image data value of each pixel in said image, and obtaining an average value of image data of pixels in each of a plurality of rectangular regions defined as a plurality of rows and a plurality of columns in said image, in turn in the row direction, said method comprising the steps of:

obtaining an average value of image data values of pixels in a first rectangular region by using an average value of image data values of pixels in a second rectangular region which was processed previously to calculate an average value of image data values of pixels in said first rectangular region, having a partial region in common with said rectangular region, and using a difference between image data values of pixels included in said first rectangular region and excluded from said

second rectangular region and image data values of pixels included in said second rectangular region and excluded from said first rectangular region;

wherein said difference is calculated by using a first image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said first rectangular region and excluded from said second rectangular region, image data values of which have been read out previously to calculate said average value of image data values of pixels in said first rectangular region, a second image data value of the bottom pixel in said area of pixels included in said first rectangular region and excluded from said second rectangular region, a third image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said second rectangular region and excluded from first second rectangular region, a fourth image data value of the bottom pixel in said area of pixels included in said second rectangular region and excluded from said first rectangular region.

2. An image processing method of reading image data of pixels in an image to be processed, from a memory for storing an image data value of each pixel in said image, and obtaining a sum of image data of pixels in each of a plurality of rectangular regions defined as a plurality of rows and a plurality of columns in said image, in turn in the row direction, said method comprising the steps of:

obtaining a sum of image data values of pixels in a first rectangular region by using a sum of image data values of pixels in a second rectangular region which was processed previously to calculate a sum of image data values of pixels in said first rectangular region, having a partial region in common with said rectangular region, and using a difference between image data values of pixels included in said first rectangular region and excluded from said second rectangular region and image data values of pixels included in said second rectangular region and excluded from said first rectangular region;

wherein said difference is calculated by using a first image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said first rectangular region and excluded from said second rectangular region, image data values of which have been read out previously to calculate said sum of image data values of pixels in said first rectangular region, a second image data value of the bottom pixel in said area of pixels included in said first rectangular region and excluded from said second rectangular region, a third image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said second rectangular region and excluded from first second rectangular region, a fourth image data value of the bottom pixel in said area pixels included in said second rectangular region and excluded from said first rectangular region.

3. An image processing method of reading image data of pixels in an image to be processed, from a memory for storing an image data value of each pixel in said image, and obtaining a sum of squares of image data values of pixels in each of a plurality of rectangular regions defined as a plurality of rows and a plurality of columns in said image, in turn in the row direction, said method comprising the steps of:

obtaining a sum of squares of image data values of pixels in a first rectangular region by using a sum of squares of image data values of pixels in a second rectangular region which was processed previously to calculate a sum of squares of image data values of pixels in said first rectangular region, having a partial region in common with said rectangular region, and using a difference between image data values of pixels included in said first rectangular region and excluded from said second rectangular region and image data values of pixels included in said second rectangular region and excluded from said first rectangular region;

wherein said difference is calculated by using a first image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said first rectangular region and excluded from said second rectangular region, image data values of which have been read out previously to calculate said sum of squares of image data values of pixels in said first rectangular region, a second image data value of the bottom pixel in said area of pixels included in said fist rectangular region and excluded from said second rectangular region, a third image data value of a pixel neighboring the top pixel at the upper side of said top pixel in an area of pixels included in said second rectangular region and excluded from first second rectangular region, a fourth image data value of the bottom pixel in said area of pixels included in said second rectangular region and excluded from said first rectangular region.