Image reading device
AssigneeAsahi Kogaku Kogyo Kabushiki Kaisha
InventorYasuhiro Yamamoto
Life of this patent
Estimating the term…
Abstract
The image reading device has a pixel data reading processor, in which pixel data forming an image is read, and a histogram generating processor, in which a histogram representing a distribution of the pixel data is generated. The histogram is utilized when determining an optimum exposure time, for example. In the generation of the histogram by the histogram generating processor, not all of the pixel data are used. Namely, pixel data, from the maximum value through a first boundary value, and pixel data, from a second boundary value through the minimum value, are used. Since the pixel data, from the first boundary value through the second boundary value, are not utilized in generating the histogram, the capacity of the memory, in which the histogram is stored, can be reduced.
Claims10
An image reading device, comprising:
- a pixel data reading processor that reads pixel data forming an image, each of said pixel data having a value included in a first range;
- a histogram generating processor that generates a histogram representing a distribution of said pixel data having values included only in a second range which is a part of said first range, said histogram generating processor generates said histogram based on pixel data of said second range which are included in an upper portion, from a maximum value of said first range to a first boundary value which is lower than said maximum value, and a lower portion, from a minimum value of said first range to a second boundary value which is lower than said first boundary value and higher than said minimum value;
- and
- a data storage processor that stores data related to said histogram generated by said histogram generating processor, said data storing processor stores first data, related to said upper portion of said pixel data and second data, related to said lower portion of said pixel data, in successive addresses of a memory.
An image reading device, comprising:
- a pixel data reading processor that reads pixel data forming an image;
- a histogram generating processor that generates a histogram representing a distribution of only a part of said pixel data read by said pixel data reading processor, said histogram generating processor generates said histogram based on pixel data which are included in an upper range from a maximum value of said image forming pixel data to a first boundary value which is lower than said maximum value, and a lower range from a minimum value of said image forming pixel data to a second boundary value which is lower than said first boundary value and higher than said minimum value,
- a data storing processor that stores data related to said histogram generated by said histogram generating processor, said data storing processor stores first data, related to said upper range of said pixel data and second data, related to said lower range of said pixel data in successive addresses of a memory.
An image reading device, comprising:
- means for reading pixel data which forms an image, each of said pixel data having a value included in a first range;
- means for generating a histogram representing a distribution of said pixel data having values included only in a second range which is part of said first range, said histogram generating means generating said histogram based on pixel data of said second range which are included in an upper portion, from a maximum value of said first range to a first boundary value which is lower than said maximum value, and in a lower portion, from a minimum value of said first range to a second boundary value which is lower than said first boundary value and higher than said minimum value;
- and
- means for storing data related to said histogram generated by said histogram generating means, said data storing means stores first data, related to said upper portion and second data, related to said lower portion in successive addresses of a memory.
Dependencies are inferred from the claim text.