WO2006036921A1

WO2006036921A1 - Image capturing device

Info

Publication number: WO2006036921A1
Application number: PCT/US2005/034500
Authority: WO
Inventors: Senshu Igarashi
Original assignee: Eastman Kodak Company
Priority date: 2004-09-28
Filing date: 2005-09-27
Publication date: 2006-04-06

Abstract

There is provided an image capturing device such as a digital camera in which desired captured results can be obtained by intuitive operations. An image signal from a CCD is stored in a memory while also being displayed on a display unit as the captured result. When the user is dissatisfied with the captured result, the user operates a deletion switch provided in an operation input unit, and further operates a deletion reason switch to selectively input a reason for the deletion. In response to the input deletion reason, a microcomputer controls the amount of light emission by a strobe, the shutter speed, and the like. When the deletion reason is 'washed-out face', the microcomputer reduces the amount of light emission by the strobe.

Description

IMAGE CAPTURING DEVICE

FIELD OFTHE INVENTION

The present invention relates to an image capturing device, and more particularly to adjustments in an image capturing device such as a digital camera.

BACKGROUND OF THE INVENTION

An image capturing device such as a digital camera is provided with functions for adjusting various parameters, including the functions of white balance adjustment and exposure correction, in order to allow a user to obtain desired images.

However, especially in the recent years, as a result of enhanced size reduction and incorporation of many more functions in digital cameras or the like, it has become increasingly difficult for general users to understand the functions provided in a digital camera and to appropriately and selectively employ those functions in accordance with image capturing conditions.

Japanese Patent Laid-Open Publication No. 2001-36780 discloses a technique of dividing a display portion of a monitor display device into a first display portion and a second display portion, and displaying a predetermined menu in the first display portion while displaying items related to the menu in the second display portion, to thereby facilitate camera operation.

When the functions provided in a digital camera are simply displayed as a menu, camera operation is not particularly easy because a knowledge of the functions is required. For example, when the menu of "slow synchronization" is displayed, the display is meaningless for a user if the user does not know what the function of slow synchronization is, and under which photographing conditions this function should be used. A typical user generally wishes to change settings of a digital camera when they see an image which was photographed under the current settings of the digital camera and is dissatisfied with the obtained image concerning specific points. It would be desirable if, in such a case, the user could make use of various functions via intuitive operations without having technical knowledge of digital camera functions.

SUMMARY OF THE INVENTION

The present invention provides an image capturing device in which various functions are automatically set or adjusted by an intuitive operation performed by a user. The intuitive operation refers to the user seeing a captured result, and, when they have a specific reason for being dissatisfied with the captured result, inputting the intuitive reason. With this arrangement, a desired image can be obtained very easily.

An image capturing device according to the present invention comprises a strobe unit for irradiating strobe light on an object, an image capturing unit for photoelectrically converting light conveyed from the object and outputting an image signal obtained by the photoelectric conversion, a light amount adjustor for adjusting an amount of incident light introduced into the image capturing unit, a gain adjustor for adjusting a gain of the image signal output from the image capturing unit, a white balance adjustor for adjusting white balance of the image signal which has been processed by the gain adjustment, a gamma corrector for performing gamma correction with respect to the image signal, and a display unit for displaying, as a captured result, the image signal which has been processed by the white balance adjustment and the gamma correction. The image capturing device further comprises a deletion switch for receiving an input of an instruction for deleting the captured result, a deletion reason switch for receiving a selective input of a reason for deleting the captured result, and a control unit for integrally controlling operations of the strobe unit, the gain adjustor, the light amount adjustor, the white balance adjustor, and the gamma corrector in accordance with the input reason for deletion.

According to the above-described arrangement, a captured result is displayed, and if, upon seeing the captured result, the user is dissatisfied and wishes to delete the result, the user inputs a reason for deletion. In accordance with the selectively input reason for deletion, the control means controls the components of the image capturing device such as the strobe unit and the light amount adjustor, so as to adjust the amount of strobe light emission, exposure, and the like. As such, according to the present invention, the user can obtain a desired image by simply selectively inputting an intuitive reason for deletion without being aware of the respective components such as the strobe unit and the light amount adjustor.

According to one aspect of the present invention, the input reason for deletion may be, for example, a reason related to the overall darkness of the captured result (such as "the captured result appears too dark"), a reason related to colors of the captured result (such as "the colors of the captured result are unnatural"), a reason related to blurred contours in the captured result, a reason related to luminance of a person's face portion in the captured result (such as "the face is shadowed" and "the face is washed out") a reason related to luminance of the background in the captured result (such as "the background appears too dark"), and a reason related to the color of the sky in the captured result (such as "the clear sky appears whitish in the image"). In accordance with these reasons for deletion, the control unit makes adjustments by increasing or decreasing the amount of light emission by the strobe unit and the exposure adjusted by the light amount adjustor. According to the present invention, a user can obtain a desired captured result by simply inputting an intuitive reason for deletion. Because the user can adjust the strobe unit, the light amount adjustor, and the like by simply selectively inputting an intuitive reason for deletion, the user can effectively make use of the functions of the image capturing device without having precise knowledge of those functions.

BRIEF DESCRIPTION OFTHE DRAWINGS

Fig. 1 is a block diagram showing an overall configuration of an embodiment of the present invention. Fig. 2 is a functional block diagram showing the image processing unit of Fig. 1. Fig. 3 is a functional block diagram showing the operation input unit of Fig. 1.

Fig. 4 is a diagram for explaining a display screen which indicates a list of reasons for deletion. Fig. 5 is a first flowchart showing the adjustment processing performed by the microcomputer in accordance with a reason for deletion.

Fig. 6 is a second flowchart showing the adjustment processing performed by the microcomputer in accordance with a reason for deletion.

Fig. 7 is a graph showing the relationship between the maximum reflectance and the gamma correction value.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, a preferred embodiment of the present invention is next described using a digital camera as an example. Fig. 1 is a block diagram showing an overall configuration of a digital camera according to a preferred embodiment of the present invention. A lens 10 converges light conveyed from an object. A diaphragm (aperture) 12 and shutter 13 adjust the amount of incident light from the object and the duration of incidence, respectively. Alternatively, without providing the mechanical shutter 13, the duration of incidence can be adjusted by controlling the charge accumulation time of a CCD 14 based on a drive signal supplied from a timing generator (TG) 34 described later (this arrangement is referred to as an electronic shutter). It is also possible to provide both the mechanical shutter 13 and the electronic shutter. Light which has been subjected to convergence and light amount adjustment by the lens 10, diaphragm 12, and shutter 13, is introduced into the CCD 14 which serves as an image capturing element. The CCD 14 converts the incident light into an electrical signal (voltage signal) in accordance with the amount of light. Instead of the CCD 14, a CMOS device may alternatively be employed as the image capturing element. The CCD 14 outputs the electrical signal obtained by photoelectric conversion to a CDS/AGC 16.

The CDS(correlated double sampling)/ AGC(automatic gain control) 16 samples the electrical signal from the CCD 14, adjusts the signal level (gain), and outputs the obtained signal to an A/D converter 18. The A/D 18 converter converts the analog signal from the CDS/AGC 16 into a digital signal, and outputs the digital signal to an image processing unit 20. The image processing unit 20 is composed of a system LSI. The image processing unit 20 performs a predetermined signal processing on the input digital signal, and outputs the processed signal to a CODEC 22 or D/ A converter 26.

Fig. 2 is a functional block diagram of the image processing unit 20. The image processing unit 20 sequentially executes, with respect to the digital signal (digital image signal) supplied from the A/D 18, the processes of white balance correction, gamma (γ) correction, and separation into color signal and luminance signal.

A white balance correction processor 20a corrects the balance among the respective colors in the digital image signal supplied from the A/D 18 based on factors such the differences between filter sensitivities of the respective color filters provided in the CCD 14, and outputs the corrected image signal to the gamma correction processor 20b. A gamma correction processor 20b performs gamma correction with respect to the image signal which has been subjected to white balance correction. The gamma correction processor 20b exponentially converts the input values to obtain output values conforming to the characteristic of the display device, so as to ensure linearity. More specifically, the gamma correction is executed by storing in a memory the relationship between input values and output values as a map, and accessing the map to obtain an output value corresponding to an input value. For an intermediate value which is not defined in the map, interpolation is performed using neighboring values (values on both sides). Instead of using a map, the gamma correction may alternatively be performed by storing a gamma correction function and using this correction function to calculate conversions. The gamma correction processor 20b outputs a gamma-corrected digital image signal to an RGB signal generation processor 20c. The RGB signal generation processor 20c performs, with respect to the input digital image signal, processing such as noise removal, bandwidth restriction, and high frequency signal correction, generates R signal, G signal, and B signal, and outputs those signals to a luminance signal generation processor 2Od and a chrominance signal generation processor 2Oe. The luminance signal generation processor 2Od generates a luminance signal (Y signal) by synthesizing the RGB signals supplied from the RGB signal generation processor 20c at a predetermined synthesis ratio. Further, the chrominance signal generation processor 2Oe generates a chrominance signal (Cb and Cr) by similarly synthesizing the RGB signals supplied from the RGB signal generation processor 20c at a predetermined synthesis ratio. The luminance signal and chrominance signal are supplied to the CODEC 22 or D/A 26 as noted above.

Referring again to Fig. 1 , the CODEC 22 compresses the image signal supplied from the image processing unit 20, encodes the compressed image signal, and stores the encoded signal in a memory 24. The CODEC 22 also serves to expand and decode coded image data which was read out from the memory 24, and supplies the resulting data to the image processing unit 20. The memory 24 may be composed of a flash memory, and stores image data which has been compressed and encoded by the CODEC 22. The image data stored in the memory 24 may be compressed and encoded in formats such as the JPEG format and TIFF format. The D/A 26 converts the image signal supplied from the image processing unit 20 into an analog image signal for outputting to a video encoder 28. The video encoder 28 encodes the analog image signal into a video signal having a format which conforms to a display unit 30 (such as an NTSC signal), and outputs the encoded signal to the display unit 30. The display unit 30 may be composed of a liquid crystal panel, organic EL panel, or the like, and displays the image signal supplied from the video encoder 28. The display unit 30 functions as the viewfinder or image monitor of the digital camera. An operation input unit 32 is an operation switch unit via which a user of the digital camera can designate various commands and menus for shutter operation, object or scene selection, and the like. Various command signals in accordance with a switch operation are output from the operation input unit 32 to a microcomputer 36 or the image processing unit 20 via a bus. The timing generator (TG) 34 controls the operation timings of the CCD 14,

CDS/AGC 16, A/D 18, and the image processing unit 20. When the display unit 30 is to function as a viewfinder, under the control of the TG 34, image signals are sequentially stored into an internal memory (not shown) within the image processing unit 20 at a constant frame rate. The image signals stored in the internal memory are subjected to a thinning processing so as to be reduced to a predetermined image size. The reduced image signals are displayed on the display unit 30 serving as the viewfinder after being processed by the D/A 26 and the video encoder 28. When the user operates a shutter button which is a part of the operation input unit 32, the TG 34 performs control such that the image processing unit 20 captures the image signal stored within the internal memory of the image processing unit 20 at the point when the shutter button is pressed. The image signal stored at the corresponding timing is compressed and encoded by the CODEC 22 and stored in the memory 24. Alternatively, the image signal obtained at the point when the shutter is pressed is read out from the internal memory of the image processing unit 20, and is displayed on the display unit 30 (which serves as a viewfinder or image monitor) after being processed by the D/A 26 and the video encoder 28. The user looks at the screen of this display unit 30 to see and evaluate the captured result.

A strobe 2 is built in the digital camera. Occurrence of light emission and the amount of emitted light by the strobe 2 is controlled by a light generating unit 4. The light generating unit 4 is driven by a control signal supplied from the microcomputer 36. As described later in detail, the light generating unit 4 includes a main capacitor, and executes light emission of the strobe 2 composed of a xenon tube or the like by means of electrical charges accumulated in the main capacitor. When executing strobe light emission, the light generating unit 4 basically performs a pre-emission and a main emission. Light reflected by the object is detected by a photometer 6, and the detected result is supplied to the microcomputer 36.

The microcomputer 36 integrally controls the diaphragm 12, shutter 13, AGC function of the CDS/AGC 16, TG 34, image processing unit 20, and light generating unit 4. More specifically, based on shutter operation signals, various command signals, menu selection signals, and the like, which are input from the operation input unit 32, the microcomputer 36 controls the diaphragm 12, shutter 13, and AGC 16 to adjust the emitted light amount and the exposure, while also writing image data into and reading image data from the memory 24, and controlling display on the display unit 30. In order to persuade the user to operate the operation input unit 32 or to assist the user in doing so, the microcomputer 36 displays on the display unit 30 predetermined operation menus and the current status (such as photographable number of images, shutter speed, diaphragm value, setting mode, and histogram). The microcomputer 36 monitors a terminal voltage of the main capacitor within the light generation unit 4 and controls charging and discharging of the main capacitor, so as to achieve control of the pre-emission, main emission, and emitted light amount for each of those emissions by the strobe 2. In a conventional digital camera, the microcomputer 36 is configured to always execute a pre-emission along with a main emission when it is determined as a result of light detection that the object appears dark and strobe emission is necessary. In contrast, according to the present embodiment, the pre-emission is invalidated as necessary in accordance with a user's request input via the operation input unit 32, for the purpose of preventing the terminal voltage of the main capacitor from being reduced by the pre-emission and to correspondingly increase the emitted light amount during the main emission. As such, the microcomputer 36 integrally controls the diaphragm 12, shutter 13, gain of the CDS/AGC 16, and pre-emission and main emission of the strobe 2 to thereby produce a captured result desired by the user.

The light generating unit 4 comprises the main capacitor, a discharging circuit, a charging circuit, and a switch. A power source line extending from a power source circuit is connected to the charging circuit. At times when strobe emission is not required, the microcomputer 36 switches over the switch to the charging circuit side so as to allow the main capacitor to be charged. The terminal voltage of the main capacitor is supplied to the microcomputer 36 as a voltage divider signal obtained using two serially connected resistors. Using this signal, the microcomputer 36 monitors the terminal voltage of the main capacitor. When strobe emission is required, the microcomputer 36 switches over the switch to the discharging circuit side so as to discharge the charges accumulated in the main capacitor for supplying to the strobe 2. Light emission by the strobe 2 may be performed as a pre-emission and a main emission. The amount of emitted light for each of those emissions is adjusted by the terminal voltage and the duration of discharge. More specifically, the microcomputer 36 calculates an amount of light to be emitted for a pre-emission based on the terminal voltage of the main capacitor, object luminance information (luminance information prior to pre-emission), and object distance information. While the light amount for pre-emission is generally increased when the terminal voltage is greater, as long as the terminal voltage is higher than a specific value, the pre-emission light amount may be set at a constant value without considering the terminal voltage. Further, the microcomputer 36 calculates a light amount for the subsequent main emission based on the pre-emission light amount (integrated emission amount) and the reflected light amount from the object during the pre-emission. Based on the pre-emission light amount, a difference with respect to a reflected light amount obtained under natural light is calculated so as to extract the pre-emission light amount alone. An insufficient amount of light determined by referring to an optimum exposure value is used as the light amount for the main emission.

Fig. 3 shows a configuration of the operation input unit 32 of Fig. 1. The operation input unit 32 includes functional components that are typical in a digital camera, such as a power switch, release button (shutter button), menu selection switch, switch for selecting read-out of photographed images, and the like, and further comprises a deletion switch 32a and a deletion reason selection switch 32b. The deletion switch 32a is operated by the user to delete a captured result (from the memory) when, upon seeing the captured result displayed on the display unit 30, the user is dissatisfied with the captured result for some reason. The deletion reason switch 32b is a switch operated by the user subsequent to the operation of the deletion switch 32a for selectively inputting a reason for deleting the captured result. When the user operates the deletion switch 32a, a deletion command is supplied to the microcomputer 36. In response to the deletion command, the microcomputer 36 allows a list of deletion reasons to be displayed on the display unit 30 for the purpose of determining the reason for deletion.

The user then selects and inputs a deletion reason from among the list using the deletion reason switch 32b. When the user selectively inputs the deletion reason by operating the deletion reason switch 32b, a command corresponding to each deletion reason is supplied to the microcomputer 36. In accordance with the selectively input deletion reason, the microcomputer 36 integrally controls the diaphragm 12, shutter 13, gain of CDS/AGC 16, and light generating unit 4. With this arrangement, from the user's perspective, various adjustments are automatically performed in the digital camera when the user simply inputs their intuitive dissatisfaction concerning a captured result in the form of an intuitive "deletion reason", without requiring a precise knowledge of various adjusting functions of the digital camera. Fig. 4 shows an example list of deletion reasons which is displayed on the display unit 30 when the user operates the deletion switch 32a. The displayed deletion reasons may include "delete anyway", "too dark", "unnatural colors", "red eyes", "blurred", "shadowed face", "washed-out face", "dark background", "sky should appear blue", and "inappropriate for auction". "Delete anyway" is a menu to be selected when the user deletes a captured result because they are dissatisfied with the captured frame itself. "Too dark" is a menu to be selected when the captured result is dark overall and a brighter image is desired. "Unnatural colors" is a menu to be selected when the colors in the captured result appear differently from those intended. "Blurred" is a menu to be selected when the contours in the captured result are blurred. "Red eyes" is a menu to be selected when the eyes of persons in the captured result appear red. "Shadowed face" is a menu to be selected when the faces in the captured result appear shadowed. "Washed-out face" is, on the other hand, a menu to be selected when the faces in the captured result appear washed out. "Dark background" is a menu to be selected when a person or other objects in the captured result appear fine but the background appears dark or completely black. "Sky should appear blue" is a menu to be selected when the sky in the captured result does not appear blue despite the clear weather. "Inappropriate for auction" is a menu to be selected when the captured result is to be employed for a specific purpose (in this case, putting up items for auction on the Internet) and the result does not create sufficient appeal. All of these menus relate to matters which a user can intuitively recognize concerning a captured result. The microcomputer 36 determines which of these menus are selected and input, and, in accordance with each menu, controls the diaphragm 12, shutter 13, light generating unit 4, and the like following a predetermined control program.

The control performed by the microcomputer 36 in accordance with a selected deletion reason is next described. The control program is stored in a ROM within the microcomputer 36 as firmware.

Figs. 5 and 6 are flowcharts showing the control performed by the microcomputer 36. When a user photographs a desired object in the AE mode, the image processing unit 20 displays the captured result on the display unit 30 (S 101 ). The display time may be a predetermined period. In order to allow details of the captured result to be observed, a specific portion of the image can be enlarged and displayed according to a manipulation by the user. The technique of displaying a captured result on the rear monitor of a digital camera is known.

After displaying the captured result, the microcomputer 36 shifts into an input standby state waiting for a deletion command from the user (S 102). When the user operates the deletion switch 32a while in this state, in response to the deletion command, the microcomputer 36 instructs the image processing unit 20 to display on the display unit 30 a predetermined list of deletion reasons so as to persuade the user to input a reason for deletion (S 103). When the user inputs a deletion reason, the microcomputer 36 determines which deletion reason is input.

When the selected and input deletion reason is "delete anyway" (S 104), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 105). In this case, the microcomputer 36 simply executes the deletion and does not carry out any specific adjustment processing. Accordingly, when the release button is subsequently pressed, the photographing conditions are basically the same as the previous conditions.

When the selected and input deletion reason is "too dark" (S 106), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 107). Further, in response to the deletion reason "too dark", the microcomputer 36 adjusts the diaphragm 12, shutter 13, light generating unit 14, and gain of the AGC 16 to increase the exposure in order to satisfy the user's need. More specifically, the microcomputer 36 determines whether light emission by the strobe 2 was used during the previous exposure process (use or non-use of the strobe emission is stored in the internal memory within the microcomputer 36). When the strobe 2 emission is not used, that is, when there is sufficient natural light, the shutter speed of the shutter 13 is reduced so as to increase the exposure. On the other hand, when the strobe 2 emission is used, the microcomputer 36 instructs the light generating unit 4 to increase the amount of strobe light emission. As described above, during an ordinary exposure process, the strobe 2 performs a pre-emission before the main emission, and the light generating unit 4 determines the emitted light amount Q for the main emission according to a result obtained from the pre-emission. At this point in the present control procedure, the light generating unit 4 increases the emitted light amount for the main emission by ΔQ, such that the main emission amount becomes Q+ΔQ. If the increase of the main emission amount by ΔQ has already been effected during the previous exposure process, the microcomputer 36 invalidates the pre-emission and executes the main emission alone. If both the pre-emission and the main emission are performed, the terminal voltage of the main capacitor would be decreased by the pre-emission such that the maximum emissive light amount for the main emission would become reduced. By eliminating the pre-emission, the emitted light amount for the main emission can be maximized. In addition to invalidating the pre-emission of the strobe 2, the microcomputer 36 may also increase the gain of the AGC 16 so as to increase the ISO sensitivity.

When the selected and input deletion reason is "unnatural colors" (S 109), the microcomputer 36 displays on the display unit 30 a list of lighting conditions so as to persuade the user to select and input the lighting condition (S 110). The list of lighting conditions may include items such as "in the sun", "in shade", "fluorescent light", "tungsten", and "don't know". When the lighting condition is input, the microcomputer 36 responds to the deletion request from the user by deleting from the memory 24 the captured result displayed on the display unit 30 (S 111 ). Further, in response to the deletion reason "unnatural colors" and the lighting condition, the microcomputer 36 instructs the white balance correction processor 20a within the image processing unit 20 to perform white balance adjustment appropriate for the lighting condition (S 112). When "don't know" is input as the lighting condition, the microcomputer 36 executes the default white balance adjustment, which may be the adjustment appropriate for under sunlight.

When the selected and input deletion reason is "red eyes" (S 113), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (Sl 14). Further, in response to the deletion reason "red eyes", the microcomputer 36 performs a predetermined processing for preventing red eyes (S 115). Specifically, prior to the main emission, light may be emitted by the strobe 2 a few times so as to cause the pupils of an object person to contract, thereby minimizing red eyes. Other methods may alternatively be employed.

When the selected and input deletion reason is "blurred" (S 116), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (Sl 17). Further, in response to the deletion reason "blurred", the microcomputer 36 increases the gain of the AGC 16 by a predetermined amount so as to increase the ISO sensitivity (S 118). The shutter speed is also increased.

Referring to Fig. 6, when the selected and input deletion reason is "shaded face" (Sl 19), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 120). Further, in response to the deletion reason "shaded face", the microcomputer 36 allows the strobe 2 to emit light or executes exposure correction (exposure increase) by decreasing the shutter speed of the shutter 13 by a predetermined amount (S 121 ). Whether to perform strobe emission or exposure correction in order to dissolve the problem of "shaded face" is decided depending on the amount of available natural light. More specifically, the amount of natural light is detected by means of a photometric sensor, and strobe emission is performed when the detected amount is below a predetermined level, while exposure correction is performed when the detected amount exceeds the predetermined level.

When the selected and input deletion reason is "washed-out face" (S 122), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 123). Further, in response to the deletion reason "shaded face", the microcomputer 36 instructs the light generating unit 4 to reduce the amount of light emitted by the strobe 2. More specifically, while the emitted light amount of the strobe 2 is determined based on a result obtained from the pre-emission, the main emission amount Q determined by the pre-emission is reduced by Δq, such that the main emission amount becomes Q-Δq. If strobe emission was not executed during the previous exposure process, this processing is not performed (S 124). When the selected and input deletion reason is "dark background" (S 125), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 126). Further, in response to the deletion reason "dark background", if the strobe 2 emitted light during the previous exposure process, the microcomputer 36 shifts into the so-called "slow synchronization mode".

Slow synchronization is a process in which strobe emission is performed while the shutter speed is reduced, to thereby increase the amount of exposure. On the other hand, if the strobe emission was not performed during the previous exposure process, ISO sensitivity is increased by a predetermined amount by increasing the gain of the AGC 16 (S 127).

When the selected and input deletion reason is "sky should appear blue" (S 128), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 129). Further, in response to the deletion reason "sky should appear blue", the microcomputer 36 performs an adjustment to increase the maximum reflectance of the digital camera (S 130), and, in correlation with the increase of the maximum reflectance, changes the gamma correction value to a value corresponding to the maximum reflectance after the adjustment (S131). The "maximum reflectance" referred to herein is an index denoting the incident light amount corresponding to the maximum output of the CCD 14. According to the CIPA (Camera & Imaging Products Association) standard, an intermediate gradation level is employed as the sensitivity reference level. More specifically, the reference level is the luminance value (Y value; 118 for 8-bit) obtained with respect to an 18% standard neutral gray object when the digital maximum output value (255 for 8-bit) is made to correspond to 100% object reflectance. It should be noted that the luminance value with respect to an 18% gray object need not be set to the CIPA standard value of 118, and may alternatively be set to 130, for example. This value may be determined depending on how human skin should appear in the image. When the luminance value for an 18% gray object is designated, the reflectance corresponding to the digital maximum output value (namely, the, maximum reflectance) is given by the following equation:

maximum reflectance(%) = 18(%) • maximum CCD output value /

CCD output value for 18% gray object

According to the present embodiment, in the default state, the luminance for an 18% gray object after gamma correction is set to 130 (8-bit), while the maximum reflectance is set to 120%. In this default state, the CCD 14 outputs an image signal in accordance with an amount of incident light within the reflectance range between 0-120%. When an object is photographed in the default state, white wash-out, blue haze (blue sky appears whitish), and red haze (red color appears whitish) may be caused due to high luminance of the object.

Further, under a flat lighting condition (such as when photographing in a studio), the contrast of the object may become decreased. These problems are caused because the dynamic range determined by the reflectance of 0-120% is not appropriate for the photographing conditions. Accordingly, a dynamic range which matches the photographing conditions can be set by increasing or decreasing the maximum reflectance from the default value of 120%. However, if the maximum reflectance alone is simply increased or decreased (without changing the gamma correction value), the output value after gamma correction obtained with respect to the 18% gray object, which is the reference target of correct exposure, would become varied along with the increase or decrease of the maximum reflectance (18% gray becomes relatively small within the dynamic range when the maximum reflectance is increased, while 18% gray becomes relatively great when the maximum reflectance is decreased, hence resulting in changes in the output value obtained after gamma correction). As a result, the user would not be able to obtain a desired captured result, and would be required to subsequently perform additional processing by, for example, uploading the captured result to a personal computer and correcting the tone curve using image processing software. In order to avoid this disadvantage, according to the present embodiment, the gamma correction is changed in correlation with the increase and decrease of the maximum reflectance, such that a captured result conforming with the visual impression can be obtained. Fig. 7 shows example gamma values corresponding to the maximum reflectance values of 70%, 120%, and 170%, respectively. In Fig. 7, the gamma value corresponding to the default 120% is denoted by A, the gamma value for 170% by B, and the gamma value for 70% by C.

Referring again to Fig. 6, when the selected and input deletion reason is "inappropriate for auction" (S 132), in response to the deletion request from the user, the microcomputer 36 deletes the captured result displayed on the display unit 30 from the memory 24 (S 133). Further, in response to the deletion reason "inappropriate for auction", the microcomputer 36 displays on the display unit 30 a list of lighting conditions so as to persuade the user to select and input the lighting condition, and then instructs the white balance correction processor

20a of the image processing unit 20 to execute a white balance adjustment according to the lighting conditions (S 134). Because the process for photographing an item for auction is typically performed under uniform conditions (the item to be put on auction is often placed on a table and photographed under fluorescent light), a white balance adjustment appropriate for this condition may be executed. As described above, according to the present embodiment, based on an intuitive deletion reason input by the user, elements such as the diaphragm 12, shutter 13, the amount of light emitted by the strobe 2, and the gain of the AGC 16 (ISO sensitivity) are controlled individually or integrally while combining these elements with predetermined priority, so as to attain a captured result desired by the user. As a result, the user can effectively make use of various functions of the digital camera without having precise knowledge of those functions.

While the preferred embodiment has been described above, the present invention is not limited to the described embodiment, and various changes can be made thereto.

For example, while the strobe 2 and the like are adjusted according to the selected and input deletion reason in the above embodiment, it is preferable to cancel those adjustments when a predetermined period of time has passed after the previous exposure process, such that those adjustments are not executed during the subsequent exposure process. After passage of the predetermined period, it can be judged that the photographing conditions have changed from the conditions which required those adjustments. Specifically, the passage of the predetermined period can be determined by means of a timer. If the digital camera is provided with a function for shifting into the sleep mode or the power OFF state when no operations are performed over a specified period of time, the adjustment cancellation can be executed in combination with this function. That is, the adjustments may be cancelled when the digital camera shifts into the sleep mode or the power OFF state. Further, it may be possible to allow the user to appropriately select whether or not to display the list of deletion reasons.

It may also be preferable to indicate on the display unit 30, for the purpose of notifying the user, whether the microcomputer 36 made adjustments in the strobe 2 and the like in order to overcome the deletion reason. With this arrangement, the user can clearly recognize that the digital camera has now shifted from the default state to an adjustment mode for overcoming the deletion reason. The user may terminate the adjustment mode by turning off the power, for example. In response to the turning off of power, the microcomputer 36 performs controls to reset the strobe 2, shutter 13, AGC gain (ISO sensitivity), and the like to the default state.

While adjustment control is performed in accordance with the deletion reason in the above embodiment, the digital camera may be provided with the so-called learning function, as a result of which the adjustment control is adaptively changed according to a re-input of a deletion instruction or deletion reason with respect to a captured result obtained after effecting an adjustment. For example, when the microcomputer 36 executed exposure correction as an adjustment in response to the input of deletion reason "shadowed face" in S 119, and the user once again deletes the subsequent captured result photographed with the adjustment in effect and inputs the deletion reason "shadowed face", the next adjustment is executed using strobe emission. The digital camera learns from the second input of deletion reason "shadowed face" in addition to the first input of deletion reason "shadowed face" that the user desires a further increase in the amount of exposure. Accordingly, an adjustment by strobe emission instead of exposure correction is executed for the subsequent exposure processes. In another example in which the microcomputer 36 increases the maximum reflectance from the default 120% to 150% in response to the input of deletion reason "sky should appear blue" in S 128, and the user once again inputs the deletion reason "sky should appear blue" with respect to the subsequently captured result photographed with the adjustment in effect, the digital camera may learn that the initial increase from 120% to 150% was not sufficient for the user. Consequently, taking into consideration the initial input of deletion reason "sky should appear blue", an increase to 200% may be executed in the subsequent exposure process.

While the deletion reason is input after the user operation of the deletion switch 32a in the above embodiment, a list of reasons for dissatisfaction may be displayed on the display unit 30 to input a reason for dissatisfaction without deleting the captured image, thereby allowing a user to input the reason for dissatisfaction selected from the list. Then, the microcomputer 36 performs the above-described operations in accordance with the input reason for dissatisfaction. Further, while the captured image is deleted from the memory 24 by operating the deletion switch 32a, data of the captured image may be retained in a directory even when the deletion switch 32a is operated, to redisplay the deleted image later on the display unit 30 through operation (for example, recovery operation) by a user for allowing comparison between the deleted image and a retaken image. For example, the captured image may be moved to a "Recycle Bin" directory by operating the deletion switch 32a, and thereafter moved back to the previous directory from the "Recycle Bin" directory as needed. In other words, the deletion performed through operation of the deletion switch 32a according to this embodiment includes a removal action of retaining the data of the captured image in any location for later recovery operation in addition to an action of actually deleting the data of the captured image.

Claims

WHAT IS CLAIMED IS:

1. An image capturing device comprising: a strobe unit for irradiating strobe light on an object; an image capturing unit for photoelectrically converting light conveyed from the object and outputting an image signal obtained by the photoelectric conversion; a light amount adjustor for adjusting an amount of incident light introduced into the image capturing unit; a gain adjustor for adjusting a gain of the image signal output from the image capturing unit; a white balance adjustor for adjusting white balance of the image signal which has been processed by the gain adjustment; a gamma corrector for performing gamma correction with respect to the image signal; and a display unit for displaying, as a captured result, the image signal which has been processed by the white balance adjustment and the gamma correction; wherein the image capturing device further comprises: a deletion switch for receiving an input of an instruction for deleting the captured result; a deletion reason switch for receiving a selective input of a reason for deleting the captured result; and a control unit for integrally controlling operations of the strobe unit, the gain adjustor, the light amount adjustor, the white balance adjustor, and the gamma corrector in accordance with the input reason for deletion.

2. A device as defined in Claim 1 , wherein a reason related to darkness of the captured result is included in the reason for deletion; and when the reason related to darkness of the captured result is input via the deletion reason switch, the control unit controls operation of the light amount adjuster so as to adjustively increase or decrease an amount of exposure.

3. A device as defined in Claim 2, wherein the light amount adjustor comprises a shutter; and the control unit adjustively increases or decreases the amount of exposure by increasing or decreasing a shutter speed of the shutter.

4. A device as defined in Claim 1 , wherein a reason related to colors of the captured result is included in the reason for deletion; and when the reason related to colors of the captured result is input via the deletion reason switch, the control unit controls operation of the white balance adjustor so as to change the white balance.

5. A device as defined in Claim 1 , wherein a reason related to blurred contours in the captured result is included in the reason for deletion; and when the reason related to blurred contours in the captured result is input via the deletion reason switch, the control unit controls operation of the gain adjustor so as to increase the gain, and increases a shutter speed of a shutter.

6. A device as defined in Claim 1 , wherein a reason related to luminance of a human face in the captured result is included in the reason for deletion; and when the reason related to luminance of a human face in the captured result is input via the deletion reason switch, the control unit controls operation of the strobe unit so as to adjust an amount of light emitted from the strobe.

7. A device as defined in Claim 1, wherein a reason related to luminance of a human face in the captured result is included in the reason for deletion; and when the reason related to luminance of a human face in the captured result is input via the deletion reason switch, the control unit controls operation of the light amount adjustor so as to increase or decrease an amount of exposure.

8. A device as defined in Claim 1, wherein a reason related to background luminance of the captured result is included in the reason for deletion; and when the reason related to background luminance of the captured result is input via the deletion reason switch, the control unit controls operations of the strobe unit and the light amount adjustor so as to increase or decrease an amount of exposure.

9. A device as defined in Claim 1 , wherein a reason related to background luminance of the captured result is included in the reason for deletion; and when the reason related to background luminance of the captured result is input via the deletion reason switch, the control unit controls operation of the gain adjustor so as to increase or decrease the gain.

10. A device as defined in Claim 1 , wherein a reason related to sky color in the captured result is included in the reason for deletion; and when the reason related to sky color in the captured result is input via the deletion reason switch, the control unit controls at least one of the light adjustor and the gain adjustor so as to shift a dynamic range, while also changing a gamma correction value of the gamma corrector.

11. A device as defined in Claim 1 , wherein a reason related to inappropriateness of the captured result for an application is included in the reason for deletion; and when the reason related to inappropriateness of the captured result for an application is input via the deletion reason switch, the control unit controls operation of the white balance adjuster so as to change the white balance.

12. A device as defined in any one of Claims 1-11, wherein when the same reason for deletion is again input with respect to a captured result obtained after effecting control in accordance with the initially input reason for deletion, the control unit changes an amount of control according to the reason for deletion.

13. An image capturing device comprising: an image capturing unit for photoelectrically converting light from an object and outputting an image signal ; a light amount adjustor for adjusting an amount of incident light introduced into the image capturing unit; a gain adjustor for adjusting a gain of the image signal output from the image capturing unit; a white balance adjustor for adjusting white balance of the image signal ; a gamma corrector for performing gamma correction with respect to the image signal; and a display unit for displaying, as a captured result, the image signal which has been processed by the white balance adjustment and the gamma correction; wherein the image capturing device further comprises: an input unit for inputting a reason for being dissatisfied with the captured result displayed on the display unit; and a control unit for controlling operation of at least one of the light amount adjustor, the gain adjustor, the white balance adjustor, and the gamma corrector in accordance with the input reason.

14. A device as defined in Claim 13, further comprising: a strobe unit for irradiating strobe light on an object, wherein the control unit controls operation of at least one of the strobe unit, the light amount adjustor, the gain adjustor, the white balance adjustor, and the gamma corrector in accordance with the input reason.