Systems and methods for generating time delay integration color images at increased resolution
A method for generating time delay integration color images at increased resolution includes (a) capturing sequential digital two-dimensional color images of a scene using an area scan color image sensor including lines of color sensor pixels, wherein each color sensor pixel including a Bayer-type array of photosites, and (b) processing the sequential digital two-dimensional color images to generate a time delay integration color image of an object moving in the scene, wherein the processing includes increasing resolution of the time delay integration color image by including crossover pixels formed by combining photosites from sequentially captured two-dimensional color images.
1. A method for increasing resolution of a time delay integration color image, comprising:
receiving a sequence of color images captured by an area scan color image sensor, each of the color images having color-pixel lines, each of the color-pixel lines comprising:
a first row of photosite values obtained from a corresponding row of first-type and second-type photosites of the area scan color-image sensor; and
a second row of photosite values obtained from a corresponding row of second-type and third-type photosites of the area scan color-image sensor;
integrating a first series of rows into an integrated row, each of the first series of rows being the first row of one color-pixel line of a corresponding one of the sequence of color images;
integrating a second series of shifted rows into an integrated shifted row, each of the second series of shifted rows being the second row of one color-pixel line of a corresponding one of a shifted sequence of the color images;
combining the integrated row and the integrated shifted row into a line of crossover pixels; and
generating the time delay integration color image to include the line of crossover pixels.
2. The method of claim 1 , further comprising outputting the time delay integration color image to an external processing system.
3. The method of claim 1 , wherein:
the time delay integration color image alternates between even lines and odd lines; and
the line of crossover pixels is one of the odd lines.
4. The method of claim 3 , further comprising:
integrating a third series of matched rows into an integrated matched row, each of the third series of matched rows being the second row of said one color-pixel line of the corresponding one of the sequence of color images; and
combining the integrated row and the integrated matched row into one of the even rows of the time delay integration color image.
5. The method of claim 1 , wherein the sequence of color images and the shifted sequence of the color images are shifted by one color image.
6. The method of claim 1 , wherein the sequence of color images was captured at a frame rate such that an image of an object moves across the area scan color image sensor at a rate of one line per frame.
7. The method of claim 1 , the first-type photosites being sensitive to red light, the second-type photosites being sensitive to green light, the third-type photosites being sensitive to blue light.
8. The method of claim 1 , wherein:
the sequence of color images alternate between even-numbered images and odd-numbered images;
each of the first series of rows is the first row of one color-pixel line of a corresponding one of the even-numbered images; and
each of the second series of shifted rows is the second row of one color-pixel line of a corresponding one of the odd-numbered images.
9. The method of claim 8 , wherein the sequence of color images was captured at a frame rate such that an image of an object moves across the area scan color image sensor at a rate of half a line per frame.
10. A system for increasing resolution of a time delay integration color image, comprising:
an area scan color image sensor configured to capture a sequence of color images, each of the color images having color-pixel lines, each of the color-pixel lines comprising:
a first row of photosite values obtained from a corresponding row of first-type and second-type photosites of the area scan color-image sensor; and
a second row of photosite values obtained from a corresponding row of second-type and third-type photosites of the area scan color-image sensor; and
image processing circuitry configured to:
integrate a first series of rows into an integrated row, each of the first series of rows being the first row of one color-pixel line of a corresponding one of the sequence of color images;
integrate a second series of shifted rows into an integrated shifted row, each of the second series of shifted rows being the second row of one color-pixel line of a corresponding one of a shifted sequence of the color images;
combine the integrated row and the integrated shifted row into a line of crossover pixels; and
generate the time delay integration color image to include the line of crossover pixels.
11. The system of claim 10 , further comprising an interface for outputting the time delay integration color image to an external processing system.
12. The system of claim 10 , wherein:
the time delay integration color image alternates between even lines and odd lines; and
the line of crossover pixels is one of the odd lines.
13. The system of claim 12 , the image processing circuitry being further configured to:
integrate a third series of matched rows into an integrated matched row, each of the third series of matched rows being the second row of said one color-pixel line of the corresponding one of the sequence of color images; and
combine the integrated row and the integrated matched row into one of the even rows of the time delay integration color image.
14. The system of claim 10 , the area scan color image sensor being configurable to capture the sequence of color images at a frame rate such that an image of an object moves across the area scan color image sensor at a rate of one line per frame.
15. The system of claim 10 , the first-type photosites being sensitive to red light, the second-type photosites being sensitive to green light, the third-type photosites being sensitive to blue light.
16. The system of claim 10 , wherein:
the sequence of 2D color images alternate between even-numbered images and odd-numbered images;
each of the first series of rows is the first row of one color-pixel line of a corresponding one of the even-numbered images; and
each of the second series of shifted rows is the second row of one color-pixel line of a corresponding one of the odd-numbered images.
17. The system of claim 16 , the area scan color image sensor being configurable to capture the sequence of color images at a frame rate such that an image of an object moves across the area scan color image sensor at a rate of half a line per frame.