Facsimile and static presentation processing – Facsimile – Picture signal generator
Reexamination Certificate
1999-08-26
2003-06-24
Lee, Cheukfan (Department: 2622)
Facsimile and static presentation processing
Facsimile
Picture signal generator
C358S474000, C358S496000, C358S408000, C348S496000
Reexamination Certificate
active
06583896
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an image reading apparatus and an image reading method, and particularly to an image reading apparatus and image reading method for reading images recorded on a photographic photosensitive material such as a photographic film.
2. Description of the Related Art
A type of conventional laboratory system for processing an image recorded on a photographic photosensitive material such as a photographic film (hereafter, referred to as “photographic film”) exists in which, firstly, a comparatively high speed, low detail preparatory reading (hereafter referred to as a “prescan”) is performed to read the image. Next, on the basis of the image data obtained from the prescan, the photometric condition for when a comparatively low speed, high detail main reading (hereafter referred to as a “fine scan”) is performed to read the image, and the processing condition of the image processing performed on the image data obtained from the fine scan are determined. The fine scan is performed in accordance with the determined photometric condition and image processing is performed on the image data obtained from the fine scan in accordance with the above-described determined processing condition.
In this type of laboratory system, two photometric systems, each provided with CCD sensor for reading the image are provided in the image reading apparatus used to read an image recorded on a photographic film with the aim of speeding up the image reading process. One photometric system is used for performing the prescan and the other photometric system is used for performing the fine scan thus allowing the prescan and fine scan to be performed in parallel.
However, in the above-described image reading apparatus equipped with two photometric systems, in both the prescan and the fine scan, a charge accumulation time of the CCD sensor and the amount of light irradiated onto the image to be read are changed in accordance with the type of the image to be read and so on. Therefore, drawbacks exist in that the overall structure of the image reading apparatus is complex and the cost thereof is high. This is explained in more detail below.
FIG. 11
is a graph showing an example of the relationship between the negative image density (input density value) and the photometric value (output density value) for a negative image from which the photomertic measurement is performed by a CCD sensor.
As is shown in
FIG. 11
, the relationship between the negative image density and the photometric value is ideally a straight line with a gradient of 45°. However, in actuality, because of the effect of offset C with respect to the input density value, the linearity of the line cannot be maintained in the high density region. When various high-accuracy processings are performed using the photometric values obtained using the CCD sensor, only the region where the line is highly linear, i.e. excluding the high-density region, can be used, leading to a narrow dynamic range.
Two methods can be considered in order to increase the linearity of the high-density region. In one method, the amount of light irradiated onto the negative image is increased, while in the other method, the charge accumulation time is changed. The above described image reading apparatus equipped with two photometric systems, however, is structured so that the amount of light and the charge accumulation time can be adjusted for each photometric system. Therefore, the structure of each photometric system is complex and the cost of the overall device is high.
The present invention was conceived in order to solve the above-described drawbacks and the objective thereof is to provide an image reading apparatus and an image reading method which can perform a rapid image reading at a low cost.
SUMMARY OF THE INVENTION
In order to achieve the above objective, the image reading apparatus according to the first aspect of the present invention comprises:
transporting means for transporting a photographic photosensitive material on which an image is recorded in such a way that the image passes in sequence over a first reading position and a second reading position;
a first photometric system which is provided with a first light source for irradiating light onto the image at the first image reading position and which is also provided with a first image sensor for reading with fixed photometric condition the image and outputting the image as image data on the basis of one of the light transmitted through the image or the light reflected from the image;
a second photometric system which is provided with a second light source for irradiating light onto the image at the second image reading position and which is also provided with a charge accumulation-type second image sensor for reading the image and outputting the image as image data on the basis of one of the light transmitted through the image or the light reflected from the image; and
control means for controlling the second photometric system in such a way that the image is read by changing at least one of amount of light irradiated from the second light source and a charge accumulation time of the second image sensor on the basis of the image data output from the first image sensor.
According to the image reading apparatus of the first aspect of the present invention, a photographic photosensitive material having an image recorded thereon is transported by the transporting means so that the image passes in sequence through the first reading position and the second reading position.
Light is irradiated onto the image at the first reading position by the first light source provided in the first photometric system. The image is then read by the first image sensor provided in the first photometric system on the basis of the light transmitted through the image or the light reflected from the image with the photometric condition in a fixed state, and the image is output as image data. Light is then irradiated onto the image at the second reading position by the second light source provided in the second photometric system. The image is then read by the charge accumulation-type second image sensor provided in the second photometric system on the basis of the light transmitted through the image or the light reflected from the image, and the image is output as image data. Note that the type of sensor used as the above-described first image sensor includes all types of photoelectrically convertible sensors such as a silicon photodiode in addition to charge accumulation-type image sensors. While the type of sensor used as the second image sensor includes CCD-type sensors and MOS-type sensors. Moreover, the amount of light irradiated from the above first light source and the charge accumulation time when the above first image sensor is a charge accumulation-type sensor are included in the photometric condition.
At this stage, when the image is being read by the above-described second photometric system, the second photometric system is controlled so that the image is read with at least one of the amount of light irradiated from the second light source and the charge accumulation time of the second image sensor being changed by the control means on the basis of the image data output from the first image sensor.
Namely, for example, as was mentioned above, when the image data obtained from the prescan is used for determining the photometric condition and so on for performing the fine scan, even if the linearity of the above image data is comparatively low there is no problem, however, the image data obtained from the fine scan is used for outputting an actual image which means that a high linearity is required.
Accordingly, the prescan can be performed by the first photometric system of the present invention in which an image is read with the above-described photometric condition in a fixed state. By structuring the first photometric system in this way, the structure of the first photometric system can be simplified (i.e. be of a lesser quality than
Ishizaka Hideo
Ozawa Yoshio
Suzuki Kenji
LandOfFree
Image reading apparatus and image reading method does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Image reading apparatus and image reading method, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Image reading apparatus and image reading method will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3162135