Method and apparatus for positional detection using pattern matching process

A method comprising the steps of:

• generating a first signal representing an image of an object to be inspected;
• selecting portions of the first signal as second signals respectively, the second signals representing respective partial images of the inspected-object image, the partial image being of a given size, wherein each of the partial images is divided into a plurality of zones, and each of the second signals has components corresponding to the zones respectively;
• comparing the second signals with a third signal representing a predetermined reference image of a size equal to the size of the partial images, executing pattern matching between the partial images and the reference image, and calculating scores of the pattern matching between the partial images and the reference image, wherein the reference image is divided into a plurality of zones corresponding to the zones of each of the partial images respectively, and the third signal has components corresponding to the zones respectively;
• selecting a maximum score from among the calculated scores;
• generating a fourth signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;
• designating each of the zone-corresponding components of the third signal as one of an unreliable zone-corresponding component and a reliable zone-corresponding component according to a fifth signal representing predetermined valid and invalid image zones;and
• excluding the unreliable-designated zone-corresponding components of the third signal from the pattern matching;
• wherein the zone-corresponding components of the third signal designated as unreliable zone-corresponding components are zone-corresponding components which fail to accurately indicate actual appearances of corresponding portions of the reference image due to reflection of light.

A method comprising the steps of:

• generating first bit maps each having a plurality of bits, the first bit maps representing partial images of an image of an object to be inspected respectively, wherein each of the partial images is divided into a plurality of zones corresponding to the bits of the related first bit map respectively;
• comparing the first bit maps and a second predetermined bit map bit by bit, executing pattern matching between the partial images and a predetermined reference image represented by the second bit map, and calculating scores of the pattern matching between the partial images and the reference image, wherein the second bit map has a plurality of bits corresponding to the bits of each of the first bit maps, and the reference image is divided into a plurality of zones corresponding to the bits of the second bit map;
• selecting a maximum score from among the calculated scores;
• generating a signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;
• designating each of the bits of the second bit map as one of an unreliable bit and a reliable bit according to a third predetermined bit map having predetermined valid and invalid bits;
• and
• excluding the unreliable-designated bits of the second bit map from the pattern matching,
• wherein the bits of the second bit map designated as unreliable-bits fail to provide accurate indications of actual appearances of corresponding portions of the reference image due to reflection of light.

An apparatus comprising:

• means for generating a first signal representing an image of an object to be inspected;
• means for selecting portions of the first signal as second signals respectively, the second signals representing respective partial images of the inspected-object image, the partial images being of a given size;
• means for comparing the second signals with a third signal representing a predetermined reference image of a size equal to the size of the partial images, for executing pattern matching between the partial images and the reference image, and for calculating scores of the pattern matching between the partial images and the reference image;
• means for selecting a maximum score from among the scores calculated by the comparing means;
• means for generating a fourth signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;
• means for determining an invalid area of the reference image according to a fifth signal representing a predetermined unreliable image area;
• and
• means for excluding a part of the third signal, which corresponds to the invalid area of the reference image, from the pattern matching executed by the comparing means;
• wherein the predetermined unreliable image area is an area within the reference image which fails to provide an accurate indication of an actual appearance of a corresponding area of the reference image due to reflection of light.

An apparatus comprising:

• means for generating a first signal representing an image of an object to be inspected;
• means for selecting portions of the first signal as second signals respectively, the second signals representing respective partial images of the inspected-object image, the partial images being of a given size, wherein each of the partial images is divided into a plurality of zones, and each of the second signals has components corresponding to the zones respectively;
• means for comparing the second signals with a third signal representing a predetermined reference image of a size equal to the size of the partial images, for executing pattern matching between the partial images and the reference image, and for calculating scores of the pattern matching between the partial images and the reference image, wherein the reference image is divided into a plurality of zones corresponding to the zones of each of the partial images respectively, and the third signal has components corresponding to the zones respectively;
• means for selecting a maximum score from among the scores calculated by the comparing means;
• means for generating a fourth signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;
• means for designating each of the zone-corresponding components of the third signal as one of an unreliable zone-corresponding component and a reliable zone-corresponding component according to a fifth signal representing predetermined valid and invalid image zones;
• and
• means for excluding the unreliable-designated zone-corresponding components of the third signal from the pattern matching executed by the comparing means,
• wherein the zone-corresponding components of the third signal designated as unreliable zone-corresponding components are zone-corresponding components which fail to accurately indicate actual appearances of corresponding portions of the reference image due to reflection of light.

An apparatus comprising:

• means for generating first bit maps each having a plurality of bits, the first bit maps representing partial images of an image of an object to be inspected respectively, wherein each of the partial images is divided into a plurality of zones corresponding to the bits of the related first bit map respectively;
• means for comparing the first bit maps and a second predetermined bit map bit by bit, for executing pattern matching between the partial images and a predetermined reference image represented by the second bit map, and for calculating scores of the pattern matching between the partial images and the reference image, wherein the second bit map has a plurality of bits corresponding to the bits of each of the first bit maps, and the reference image is divided into a plurality of zones corresponding to the bits of the second bit map;
• means for selecting a maximum score from among the scores calculated by the comparing means;
• means for generating a signal representing a position of the partial image corresponding to the maximum score, the partial-image position being relative to the inspected-object image;
• means for designating each of the bits of the second bit map as one of an unreliable bit and a reliable bit according to a third predetermined bit map having predetermined valid and invalid bits;
• and
• means for excluding the unreliable-designated bits of the second bit map from the pattern matching executed by the comparing means,
• wherein the bits of the second bit map designated as unreliable-bits fail to provide accurate indications of actual appearances of corresponding portions of the reference image due to reflection of light.