Image sensing apparatus and method of acquiring traveling characteristics of light-shielding member

An image sensing apparatus comprising:

• an image sensing element having a plurality of pixels that converts an optical image of an object incident thereon to an electrical image signal and outputs the image signal;
• a light-shielding member that is operable to occlude an aperture to said image sensing element;
• and
• a storage means,
• wherein the apparatus further comprises:
• control means that is configured to acquire traveling characteristics of said light-shielding member based on an image signal output from a first preset partial area of said image sensing element, store the acquired traveling characteristics in said storage means, and shift the partial area to a different position spaced apart from the first preset partial area along the traveling direction of said light-shielding member, wherein
• said control means is configured to update the traveling characteristics of said light-shielding member stored in said storage means, based on an image signal from the partial area moved to said different position.

A method of estimating the traveling characteristic of the shutter blade(s) in a camera having an image sensing element including a plurality of rows of photoelectric pixels, said method comprising:

• measuring the charge accumulated in pixels in a first selected partial area of the image sensing element in a time period Tc,
• measuring the charge accumulated in pixels in a second selected partial area of the image sensing device in the time period Tc, the second selected partial area being spaced apart from the first selected partial area in the direction of travel of the shutter blade(s),
• resetting the pixels to restart charge accumulation,
• driving the shutter blade(s) to travel to stop the light from impinging upon the first and second selected partial areas of the image sensing element after a time period nominally equal to the time period Tc, but differing from Tc by different amounts because of the position/time traveling characteristic of the shutter blade(s),
• measuring the charge accumulated in the pixels in the first selected partial area of the image sensing element in the time period Ta, this time period starting with the pixel resetting operation on the first selected partial area and ending when the edge of the shutter blade(s) crosses the first selected partial area and blocks the light from impinging upon the first selected partial area,
• measuring the charge accumulated in the pixels in the second selected partial area of the image sensing element in the time period Tb, this time period starting with the pixel resetting operation on the second selected partial area and ending when the edge of the shutter blade(s) crosses the second selected partial area and blocks the light from impinging upon the second selected partial area,
• calculating from the accumulated charge measured during time periods Tc Ta and Tb the time when the edge of the shutter blade(s) cross the first and second selected partial areas, thereby providing an estimate of said traveling characteristic.